over my last 3 builds I probably could have bought one PSU instead of just upgraded to the minimum of what I needed for that build. typically for the GPU.
Warranty length, full modular, gold or higher rating, and on PSU tier list. I also agree with Viraco. This last build I bought a 1200w. Over kill for sure, but you never know what the future holds and I could have saved money on several builds if I did this instead of getting cheapest bare min. Got a ten year warranty so I plan on keeping this PSU and sending it in with any issues lol
I always go with Corsair and I look at the suggested wattage of the GPU and go like 100 more than it suggests. Always modular. As for size, whatever the case wants.