Your Mac gets a bit slow and creaky as it gets older, and we can probably all identify with that. Unlike with our stupid, weak-willed bodies, though, we don’t have to accept our Macs’ slowing down and eventual obsolescence as a crashing inevitability. There is a lot you can do to breathe new life into your aging computer to extend its useful life, and though some cost money—albeit vastly less money than it would take to buy a new Mac—many are free.

This isn’t about those wacky, cutesy projects to turn your iMac G3 into a fish tank or a Cube into a tissue dispenser, and nor is it about celebrating the zen of using an old, slow Mac that’s cut off from the Internet as a distraction-free writing tool, though there’s nothing wrong with any of that. What follows is tried-and-tested pragmatic advice to keep your Mac happily and gainfully employed for many years to come.

Understand Activity Monitor

Like a doctor, you need to understand why your Mac is sluggish before blundering in with treatments. So your first diagnostic step is to launch Activity Monitor (/Applications/Utilities) and see where the pinch points are. This will show you what applications are demanding the most from your main processor (CPU); click the %CPU column header to sort by this, and ensure you’ve selected All Processes from the View menu. If you don’t recognize a process, Google it; it might be a background app that’s run rogue.

Activity Monitor

Activity Monitor will also show you pressure on your memory (RAM). If you’re trying to run many, complex apps at once, your Mac might struggle. Start using your Mac as you would typically, and if the Memory Pressure graph on recent OSs isn’t looking full, you don’t need more RAM; on earlier systems, if the pie chart of RAM use shows mostly green and blue, the amount of RAM you have is “cool”; if it’s mostly red and yellow, you’re in hot water, and need to add more. Again, you can sort the RAM chart by Memory to see what apps are demanding RAM; consider quitting RAM-hogs if you’re not actively using them. (And don’t ever bother with “RAM cleaning” or flushing apps; OS X takes care of that for you.)

A little housekeeping

In the early days of OS X, we regularly repaired permissions and ran apps such as Cocktail or OnyX to clear caches and more to keep the system trim and tidy. These days there’s less need for that, but there’s usually no harm.

Cocktail

One good idea is to run Verify Disk in Disk Utilities (/Applications/Utilities) on your main startup disk every now and then to identify problems, and watch the SMART status for your boot drive in Disk Utility too; it’s monitoring for signs of imminent failure. Oh, and never be tempted to install MacKeeper.

Do a clean install

Usually, a Mac that has slowed further and further down has just accreted apps, files and more, and one of the surest ways of restoring the pep and vigor it had out of the box is to wipe the hard disk, install a fresh OS, and then, crucially, don’t clone everything across using Time Machine or the like. Instead, manually copy all your documents across and reinstall your apps from the App Store or CD—omitting those you don’t need.

Christopher Phin

Yes, it’s usually a colossal pain, but it’s often the most effective way to reinvigorate your Mac if you can set aside the time and accept the temporary disruption.

Swap your hard disk for an SSD

Be sure you get the right form factor. For laptops and the Mac mini, this typically means a 2.5-inch drive—though the MacBook Air has always used more exotic and different options throughout its life—while for desktops 3.5-inch drives are more usual; this isn’t a hard-and-fast rule, though, so do check your specs carefully. 3.5-inch SSDs are rare, though they do exist, but you can convert 2.5-inch drives to 3.5-inch ones with a bracket; one might even be included with your 2.5-inch SSD, but if not, buy one separately. Other World Computing even makes one specially for the 2009–2012 Mac Pro.

Check you get one with the correct connector, too. Most often these days that will mean a SATA connector, but you can buy SSDs with the older IDE/PATA/ATA connector from, say, OWC; MacBook Airs use different connectors again. Note that with older Macs (definitely true for those with IDE, but also true for those with SATA I and SATA II connections), the connection to the motherboard itself will be a bottleneck, so don’t waste your money by buying anything other than a basic SSD; you don’t get the benefit of a high-performance model. Check your specs!

Christopher Phin

Any SSD, however, will have a completely revolutionary effect on a Mac that’s only ever known a hard disk; it will feel much more responsive, and even if you have a small amount of RAM—because of how low-RAM machines swap information out to the storage drive when there’s too much for the RAM to hold, and since SSDs are much faster especially at this kind of data transfer than a hard disk—swapping to an SSD will also help even if you don’t touch the RAM.

You can just clone your old hard disk to the SSD and things will still improve, but if you can bear the hassle of combining it with a clean install, you’ll get such a fast machine you won’t recognize it.

SSDs will also likely extend the battery life of a laptop.

Add more storage—and offload files

Computers perform badly when their main storage drive is full—an oft-cited rule is to leave at least 10 percent of your drive free—so consider adding more storage and offloading files you don’t need all the time to it. This might be external storage—just plug in a USB or FireWire hard disk—but don’t forget about internal options. You can replace the optical drive in some laptops and Mac minis with a second internal drive, or use something like a Nifty MiniDrive to add more flash storage to a laptop.

Christopher Phin

Many tower Macs will support at least one additional internal drive, and in this case (or also if you install a second internal drive in a laptop at the expense of your optical drive), consider using a fast SSD as your boot drive and pairing it with a high capacity, cheap hard disk. You can even link them exactly like a Fusion Drive if you’re prepared to get your hands a little dirty in Terminal.

It might not be clear what files are taking up space on your hard disk, but apps such as DaisyDisk can help you identify them, and you can then either trash them or move them to an external drive. On very tight systems, running Monolingual can save you a decent chunk.

If you want to uninstall apps, check (including with a web search) to see if it has a proper uninstaller first. Don’t fall for “to uninstall an app on a Mac, you just have to drag it to the Trash”; search for the app’s name to find support files and caches lurking in ~/Library/Application Support and elsewhere, or—with caution!—use an app such as AppCleaner.

Upgrade your RAM

It’s hard to give absolute guidance—it depends on what you do with your Mac; check Activity Monitor as described above—but a decent rule of thumb is that 8GB RAM is pretty comfortable for most people (especially if you have an SSD), 4GB should be seen as a bare minimum, and anything under 4GB should definitely be upgraded if possible.

Christopher Phin

About This Mac will tell you how much RAM you have, and then it’s easiest to check a memory configurator at, say, crucial.com to ensure you get the right thing. Fitting RAM is one of the easiest jobs you can do so unless you’re really nervous, avoid paying someone to do it for you.

Add as much RAM as you can afford, basically; with the kind of older systems we’re talking about, in any case adding the maximum possible is unlikely to hit your wallet hard.

Replace the battery in a laptop

If your MacBook, PowerBook, or iBook is only lasting minutes away from the mains, you can replace the battery. Apple no longer makes them for older machines, but there are plenty of third-party options available. It’s your call but we’d be uncomfortable trusting a no-brand bargain from eBay; buy with a guarantee from a reputable dealer.

Christopher Phin

You might think you can’t replace the battery if it’s sealed in your MacBook, but not so. Some third-party options exist, but we’d recommend having Apple do it; follow the links on Apple’s site for costs and next steps; prices range from $129 to $199, plus taxes.

Boost the I/O

Use the fastest ports your old Mac has to connect peripherals—from slowest to fastest, it goes USB 1.1, FireWire 400, USB 2.0, FireWire 800, USB 3, Thunderbolt—but if the ports your Mac has are too slow for you, you might be able to add faster ones. You can add PCI cards for faster USB and FireWire (or even eSATA or fibre) to most tower desktop Macs, and this is also true for MacBook Pros with ExpressCard/34 slots; Sonnet makes a wide range. Check compatibility carefully, though.

Christopher Phin

You can also add faster Wi-Fi to many Macs, either with a USB or PCI adapter or by connecting an external box to an ethernet port. (Just make sure the ethernet port isn’t so old and slow it will be a bottleneck.) And remember that, say, adding 802.11ac to your Mac is pointless if you’re still running an 802.11g router; replace that too.

Add a second—or third!—display

Christopher Phin

Lots of us find ourselves more productive when we have more screen space. If your Mac can’t extend its desktop to a second screen for whatever reason, or if you’ve already added one external display but want to add more, remember that (somewhat expensive) adaptors exist to let you connect displays to USB ports. Make sure the one you pick is Mac-compatible.

Upgrade the built-in webcam—or add one

Even Apple’s latest webcams are pretty awful, which is especially irritating when adding a superb external one from the likes of Logitech is a pretty cheap investment.

Christopher Phin

Tip: If a webcam lists compatibility with Windows Vista (yes, Vista) it will work with a Mac even for as far back as the old iChat AV app, since support for Vista presupposes support for UVC; in this case, you don’t explicitly need to see Mac compatibility listed.

Install the latest OS

As soon as we suggest upgrading to the latest OS your Mac will support, we’re inviting horror stories of old Macs completely grinding to a halt under the strain, and there’s definitely a danger with older Macs that newer OSs will demand too much. But as well as the security and features benefits of the latest OS, in recent iterations not only have Apple’s system requirements stayed broadly the same, but technologies such as App Nap and compressed memory in OS X 10.10 Yosemite can actually improve performance on weaker hardware.

If you’re worried, back up your system and verify the backup, then try the latest OS your hardware supports to see if there are any problems—especially compatibility problems with software you rely on—before committing; you can always restore back from your backup.

Add newer OS features to older OSs

If you don’t want to go the whole hog and update your entire OS, you can get some of the features of modern versions of OS X by adding third-party software, such as AirParrot, Continuity Activation Tool, TotalFinder, Alfred, Growl and Filedrop. It’s even possible—if sometimes a bit hairy—to install OSs on Macs Apple doesn’t officially support.

Install a modern browser

Much of our lives these days are lived online, and if you’re stuck with an old version of Safari or even Internet Explorer then you’ll run into frequent compatibility problems. Happily, TenFourFox is a modern fork of Firefox created for G3, G4 and G5 Macs. And if you’re rocking an even older system, check out Classilla for Mac OS 9 (and even 8.6).

Use an old Mac as a server

If after all that you still think your old Mac is just too slow for day to day use, it can still lead a useful life as a server. Simply checking a box in System Preferences lets it share files—consider attaching a huge external hard disk—and if you store your iTunes Library on it you can stream that to any Mac, iOS device or Apple TV just by enabling sharing.

You could go one better and install OS X Server—a separate version of the OS prior to 10.7, but a downloadable app from the App Store in 10.7 onwards—which gives you useful options such as the ability to cache software updates locally so you’re not hammering your bandwidth, and acting as a networked Time Machine target, like a Time Capsule.

Control a Mac remotely

No room? Tuck the old Mac server away in a closet and just control it remotely; no monitor, keyboard or mouse required. Enable Screen Sharing in its System Preferences, and connect to it from the sidebar of another Mac on your local network. Or if it’s recent enough, enable Back to My Mac so you can access it even when you’re not on the same network.

Christopher Phin

You can go one better and buy Apple Remote Desktop, which gives you extra administrative and management tools.

Alternatively, connect it to the keyboard, mouse and monitor you use with your regular Mac using a KVM so you can easily toggle between them.