What upgrade to your setup made the biggest difference?

Curious what's made the most significant difference for other people working from home

For me, it was building a home gym right next to where I work. I've got a squat rack, barbell, and plates in the same room as my desk. I follow a Pomodoro-ish schedule to force myself to take real breaks — 5-minute ones, I just go sit in the sun, and for 15-minute breaks, I'll do a few quick sets of squats or bench or whatever, it's enough over the week to not need full gym sessions. Since doing this, I've noticed that when I'm actually done work for the day, I feel like I've had a day outside of work, too. If I sit on the computer ALL day I end up completely zonked at the end of the day like I just got off a plane.

The next most significant upgrade for me was a proper desk/chair. I got sent the LiberNovo Omni to beta test, which they sent me to try out since I WFH full-time. I never realized my chair was even an issue before. This has been a huge improvement, sitting and focusing is a lot easier. Now I've got a new desk too, and the whole thing feels good. It's got me trying to figure out what other ways to improve the WFH setup that I've overlooked.

What setup/routine change has made a significant impact on your WFH situation?