I stopped using a computer from a desk many years ago. This choice was decided when I wanted to use my computer via a TV on my wall. This forced my seating position in the end, which ended up being a huge benefit.
I used to use an office chair executive style, but after like 6-years, the seat deflated and was cutting off blood circulation. So I basically sit on a couch that looks like this.
The coutch seat that I have been using was also good for several years, until it wasn't anymore either. Every seat seems to deflate after its years old, don't know why, its like the foam deteriates or something. The couch was a hand me down BTW, I never bought that thing new lol.
So now I have a gell seat cushion that I sit on, you guys have actually seen it in a few of my pics where I wanted to take them fast and just didn't give a hoot about the background lol.
When your young, you have 0-problems with your body unless you have a childhood condition. Once you start getting old, aches and pains become standard, and you start worrying about your rear end more then you ever thought you would lol.