Every time Apple modifies a connector, changes a form factor, or launches a new gadget, it impacts countless companies. There’s a robust third-party market for anything and everything that attaches to or wraps around the iPhone, one that's constantly adapting to the evolving shapes, sizes, and specs of new handsets.

Now that the Apple Watch is official, we're going to see an entirely new frontier of accessories and apps.

It’s fitting that even as Apple announced the Watch, it killed the iPod Classic. The iPod was the device that created the initial wave of third-party iAccessories, from alarm clocks to speaker docks and, of course, protective cases. So many cases. With those add-ons, the iPod became more than a music player. It became a music hub. By plugging it into a secondary device, you could expand the capabilities of both.

In the pre-iPhone years, iPod accessories were a billion-dollar business. Nowadays, add-ons and cases for smartphones generate at least $20 billion in revenues, according to an ABI Research report. As Apple’s devices have grown more sophisticated, so too have the accessories available for it. There are, for example, countless lens accessories and video rigs alone now that the iPhone is the most frequently used camera in the world.

So what about this new watch? Sure, it has Siri and heart rate and motion sensors. And a really cool UI. But it doesn't have a camera, it doesn't have a headphone jack and there aren't any connectivity options. In fact, beyond its magnetic induction-charging surface, it doesn't appear to have any physical I/O ports at all.

Strapped for Cash

On the surface, that may suggest far fewer accessory opportunities, but the margins on something like a premium watchband almost certainly are higher. Apple has an MFi licensing program that blesses Apple-approved accessories with a special badge, although cases and Bluetooth components aren't included. The Apple Watch could have a similar licensing program, but the lack of electronic interfaces on the watch suggest it won't.

Watches always have been fashion items, and swappable bands are an obvious accessory for the Apple Watch. You can bet we'll see some from high-end brands, in exotic materials. Although Apple may cut into sales of conventional watches, companies that make watch accessories will profit from Apple joining the game, says Thomas Lathrop, owner of premium watch-strap maker Crown and Buckle.

"It brings a whole new level of customers that are not typical 'watch customers'," Lathrop says. "It stems from the success of the iPhone. What [Apple] could do to the smart wearable market could transform it."

Despite the opportunity to enter a new and potentially lucrative market, Lathrop says he'll take a wait-and-see approach. That's borne of more than a desire to see how successful the Apple Watch might be. Few third-party companies have had any hands-on time with the watch, so accessories must be reverse-engineered to suit its specs once it hits the market.

>"The revenue potential is there. We're already thinking about leather or wood valet holders and charging cables. We are also exploring wrist straps composed of leather, wood, and other unique materials."

Not everyone is ready to anoint the Apple Watch a cash cow. Although Apple touts the Watch as its "most personal device" ever, Roma Industries CEO Paul Horowitz says, in the realm of watches, it may not be personal enough. Roma Industries owns Hadley-Roma, which manufactures high-end watch accessories.

"[There's a] dual market for utilitarian and fashion timepieces," Horowitz says. "The real question will be if society has transformed to the point wherein technology trumps all other desires. In my opinion the watch as we know it, with complications or without, will continue to be something people aspire to, and something that changes as they change, being part of who they are. It sets them apart from the person next to them."

For established iDevice accessory companies, too, the Apple Watch is a different beast. For case maker Incase, the fact that the Apple Watch is wearable is an obstacle: Watches don't need cases.

"It's an interesting piece," says founder and CEO Tony Held, a watch collector. Held says Incase doesn't want to make Apple Watch accessories for the sake of making Apple Watch Accessories. It wants to create something "meaningful," something that adds value to the device. "It’s got to be thoughtful, not whimsical," he says. "We need to understand the user interface and how people will interact with it."

To that end, Brian Holmes, founder of Pad & Quill, a small company that makes high-end leather cases and bags for iPhones and iPads, says his team is studying how consumers can personalize the new wearable.

"The revenue potential is there, as quality timepieces have historically had various accessory options," Holmes says. "We're already thinking about leather or wood valet holders for the Apple Watch and charging cables. We are also exploring wrist straps composed of leather, wood, and other unique materials."

Given that the watch also is a fitness tracker, some sort of fully waterproof case could be a must-have for swimmers and others who play on the water. And we'll probably see belt-loop clips and other ways of wearing it on the body like a Withings Pulse or Fitbit One. Swapping bands will be a snap, but the slide-and-lock grooves that secure it to the case are a purely mechanical interface. The band doesn't interact with the watch's internal components, so we aren't likely to see a battery-charging band. That said, you can bet third-party wireless charging docks will be everywhere.

The Main Appeal

But the main appeal of the Apple Watch likely will come through its built-in accelerometer and bite-sized third-party apps. Though the watch will have its own suite of fitness apps, Apple will share workout data with other apps. The accelerometer will be used to do more than track fitness, too: Apple hinted you'll be able to control the Apple TV with it. Down the line, that kind of wrist-mounted motion sensor might be used for everything from Leap Motion-like iPad or Mac navigation to a means of moving through Oculus Rift games.

Apple demoed a few native apps that could pave the way for third-party development. The "Astronomy" watch face, which shows daily moon phases and planetary positions based on the date and time, is an example of what to expect. There certainly will be a slew of watch-optimized apps that display customized sports schedules and scores, offer "this day in history" info, and allow you to customize your watch face. It's another way to add your own style to the watch—to the extent Cook & Co. will let you, as Misty White Sidell noted in Time.

The Watch will have a remote-viewfinder app for the iPhone camera, so expect the major photo and video services to add sidecar apps that roll their own features and controls into the watch. Just as the iPhone has become a universal remote for many devices, the Apple Watch could become a next-level controller for the iPhone, iPad, TVs, and games. And it is destined to become a vital part of Apple's HomeKit initiative, both as a manual controller and as a device that can automatically adjust devices based on your movement and vitals.

There's still a lot we don't know about Apple's new timepiece, which goes on sale next year. We do know that you'll be able to use it as an Apple Pay device, a key in Starwood hotels, or a wrist-mounted dashboard for your BMW. But you can bet people will want to accessorize it, and developers will want to capitalize on it. A boom in those markets is a sure thing.