100% agree about getting a decent chair. You can make do with any old chair for a very short time, but a good chair makes ALL the difference.

I did use just a laptop (with an extra monitor at my desk) for a while as it could be used anywhere, travelling, coffee shop, client meetings etc. I found that using a laptop at home I wasn't getting as much done when trying to work away from the desk.

When my laptop needed replacing I got one of those mini-PCs for my desk and a small 10inch laptop for travelling. When that broke at about the same time we went into covid lockdown here in the UK, I decided not to replace it and just use my desktop mini-PC. I have to say that for me personally I am more productive now as desk time is work time, and time away from the desk is down-time. A much better balance IMHO having a separate workspace.

Some time ago I was doing development work for local startups, and would often meet at their homes. I remember clients who were working from their kitchen counter, right up to one client who was in the process of converting his double garage into the "perfect" home office. This particular client (it's a long time ago and I'm not mentioning any names so think I'm okay to say this) was spending thousands (GBP) on his office before the business had even earned a single penny! Priorities.

Anyway here's a pic of my desk in the corner of our spare bedroom, complete with mini-PC, speakers (I need music!) and the all important lamp with daylight bulb for the dark English winter. The monitor is at least a decade old and has outlasted maybe three or four chairs.

K