I’m an academic with neck and shoulder problems and fear turning into a hunchback through too much peering at the screen. I’m now moving house and setting up a home office. I want to dispense with my laptop – the source of my problems – and buy a desktop and an ergonomic keyboard. I’m confused about whether to get an all-in-one or a PC with a separate monitor. I am only really going to use it for internet and typing articles. I realise that this means I can look to the cheaper end of the market, but is there much slowdown in speed at that end? Should I be spending the money to get a good processor? Polly

Laptops can be considered harmful if used for prolonged serious work rather than casual use. If you have neck and shoulder problems, you should seek medical help. I’ve been saved twice by an excellent physiotherapist, at my own expense. I’ve also spent time and money mitigating problems, but there is no panacea. Buying an ergonomic keyboard is only one part of a solution that could also include the mouse, desk, chair, lighting, work habits and, perhaps, glasses.

You don’t need a computer to get a repetitive strain injury (RSI). Housemaid’s knee, tennis elbow, writer’s cramp, potter’s wrist and other afflictions are much older than iPad neck, but they all have similar causes. According to the UK’s Health and Safety Executive (HSE), the risk factors include repetitive work, the use of sustained or excessive force, awkward and static working postures, and doing the same thing for long periods without taking rest breaks. Without job rotation, that last one may be the hardest to solve, though software can help.

Unfortunately, people tend to feel invulnerable until they get an RSI. Just as losing a hard drive tends to persuade people that backups are a good idea, carpal tunnel syndrome is a great spur to taking ergonomics seriously. It’s better to do something before you reach that stage.

Furniture matters

Facebook Twitter Pinterest Catherine De Bolle, head of Europol, demonstrating how not to have your computer and desk set up for prolonged use. Photograph: Eva Plevier/Reuters

Start with a sheet of paper, a tape measure, and a friend. Drawing a stick-figure diagram with your measurements will help you find products that will work well for someone of your height.

To get the correct posture, your feet should be flat on the floor, and when sitting upright, your eyes should be roughly level with the top of the screen. Your friend can then measure the distance between your eyes and the floor. Everything else has to fit in between.

Your thighs should be parallel to the floor or pointing very slightly downwards, which will fix the height of the seat of the chair. This won’t happen by magic, which is why proper office chairs have adjustable seats.

Your arms should be roughly at right angles or pointing slightly downwards, not upwards. This will fix the height of the top of the keyboard, and possibly the height of the desk. I say “possibly” because many desks are designed for writing not typing, and will therefore be too high. One solution is a keyboard tray that slides under the desk. Some “computer desks” have trays as standard, but you can buy them separately. Wheeled computer stands do the same thing for a low price, and you can pull them out to fiddle with the wiring at the back.

As a cross-check, extend one arm horizontally. It should almost touch the centre of the screen.

When you are trying to find the most comfortable position, some tweaking is inevitable. It’s therefore better to buy products that allow for minor adjustments. You can fudge things with cushions, footrests, and books under monitors, but it’s better to do it right.

Standing desks?

Some people have switched to standing desks, and some devices provide a choice. Varidesk, for example, says that “our simple design takes you from sitting to standing in just 3 seconds, requires no assembly and works with your existing furniture”. It also has a 30-day money-back guarantee. Other options range from aiBox’s ultra-cheap cardboard version to the motorised Gazedesk, which you can set by entering your height and weight in its smartphone app.

A panel of experts commissioned by Public Health England recommended standing desks in the British Journal of Sports Medicine, so I feel guilty for never have tried one.

Ergonomic accessories

Facebook Twitter Pinterest Microsoft’s Sculpt keyboard is one of the best general ergonomic options. Photograph: Microsoft

As far as I know, nobody ships PCs with ergonomic keyboards and mice. They cost too much, they require changes to long-established typing habits, and nobody knows which products are best. However, you can start with the cheapest good options: a Microsoft Natural Ergonomic Keyboard 4000 (£43.01 on Amazon) and an Anker AK-UBA ergonomic mouse (£13.99). I’ve bought both and they are good value for money.

The Microsoft Sculpt is a better ergonomic keyboard, and you can buy one with a mouse and number pad for £74.72. However, you may find it harder to adjust to a Sculpt than to one of Microsoft’s Natural or Comfort keyboards.

Beyond this level, ergonomic keyboards become intensely personal choices. For the past few years, mine has been the Kinesis Freestyle 2. It’s a bargain if you can get one for £82.99, which is what I paid in 2016. More recently, I’ve bought a Freestyle Pro with mechanical keys (£196.74) from the helpful people at Osmond Ergonomics. This has a US layout but you can relabel the few odd keys with stickers.

An ergonomic keyboard lets you align the keys with your hands and arms, so there is no bend in your wrists. It may take months of small adjustments to reach that stage, so flexibility helps.

PC choices

Facebook Twitter Pinterest A properly configured desk, monitor, keyboard and mouse can help avoid pain. Photograph: Alamy

Technically, almost any computer system will work if you set it up correctly. I prefer tower systems, which usually last longer because they are easier to expand, upgrade and repair. They have plenty of space for cooling, so they can use hotter, faster chips with TDPs of 60W to 130W. Laptops use cooler, slower chips – typically 5W to 25W – because it’s hard to manage heat in confined spaces, and their processors are throttled when they start to overheat.

The last machine I bought, and still use, was a Dell XPS 8930 with 8GB of memory and an Intel Core i5 processor. This is a good specification to aim at, and similar PCs are available from HP, Lenovo, and dozens of small British suppliers such as Chillblast and PC Specialist. A PC with an AMD Ryzen 5 2600 processor should be as good, or slightly better.

A good cheap option would be an HP Pavilion Pentium Gold G5400, available for £349.99 from Argos. This has a much slower processor, only 4GB of memory, no graphics card, and no SSD. But at least it has an empty memory slot so you could easily add another 4GB later.

All-in-ones are tidier but they don’t have the power and expandability of a proper desktop, and you don’t get a choice of monitor. Also, if either the PC or the screen fails, you may lose both. If space is a problem, I’d rather go for an SFF (small form factor) or mini-PC instead.

Several people have asked about buying new desktops so I may return to this topic, though the “laptop for uni” questions are becoming more urgent.

Speed matters

You are right in thinking that you could get away with a slower processor and a traditional hard drive: an SSD makes less difference in a desktop where the hard drive is spinning all the time. However, there are no speed limits in computing, and it’s always better to have a faster PC. You can run more browsers with many more tabs, which would bring a slow PC to its knees.

Processor performance is complicated, but for ordinary purposes, you can reduce it to a single benchmark such as Geekbench or Passmark. For example, an Intel Core i5-9400 has a Passmark score of 11,934, while the Pentium Gold G5400 scores 5,200, which is great for the price. You can add your current laptop’s processor for comparison.

I’d rather not drop below 5,000 for a desktop, and 2,500 for a laptop that gets more casual use. Slow PCs are only cheaper if your time has no value.

Have you got a question? Email it to Ask.Jack@theguardian.com

•This article was amended on 1 August 2019 to clarify that computer users’ thighs should be parallel to the floor, not at right angles to it

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