Working from home stops being sustainable in a specific and predictable way. It is not boredom or isolation first. It is the neck, the lower back and the eyes, arriving in that order somewhere around month three, at which point the kitchen table starts to feel like the problem.
Fixing it is much cheaper than the office-furniture catalogues suggest, and the order of spending matters more than the total.
First: get the screen to eye height
This is the highest-return change available and it can cost nothing. A laptop on a table puts the screen well below eye level, and your neck holds the difference for eight hours a day. Raising it so the top of the screen sits at roughly eye height removes most of that load.
A monitor stand does it tidily. A stack of books does it for free. The important part is that once the screen goes up, the laptop keyboard becomes unusable, which means the second purchase is not optional.
Second: a separate keyboard and mouse
Inexpensive, and the thing that makes the first fix workable. With the screen raised, your hands need to be somewhere lower and closer, and that requires them to be detached from the display. Any decent set does this; there is no need to spend much.
Third: light that is not just the screen
Eye strain in a home office is usually a contrast problem, not a brightness problem. A bright screen in a dim room makes your eyes work all day. A modest lamp positioned to light the wall behind or beside the monitor evens that out for very little money.
While you are at it, move the desk so a window is beside you rather than in front of or behind you. That costs nothing and solves both glare and backlighting.
Then, and only then, the chair
Chairs are where the money goes and they are fourth for a reason. A good chair genuinely matters, but a good chair in front of a screen at chest height still leaves you with a neck problem. Fix the geometry first, then decide how much of your remaining budget the seat deserves.
If the budget is small, a lumbar cushion and a footrest recover a surprising amount from an ordinary chair. Neither is a permanent answer; both are a reasonable way to spread the cost over a few months.
The one that is not equipment
Cable management sounds cosmetic and is not. A desk you have to untangle before starting is a desk you use less. A few clips and a single tidy channel is a couple of pounds and removes a small daily friction, which over a year is the sort of thing that decides whether the setup gets used at all.
