Never replaced my PSU in all my personal builds as they have either been brand new or I've updated a different component but, depending on your case space/system complexity/location of mobo plugs...be warned. What a PITA; my CPU power connector was an absolute nightmare to remove. Thankfully my old PSU was completely modular too or I might have had to remove the mobo from the case and you don't want the added rebuild time that creates.
If anything, if you're considering a PSU replacement just plan for a system tear-down so you can clean all the accumulated dust crevices and do wire routing 10X more easily. I should've known, TBH.
Done and up and running though, so all's well. Re-installed the original Borderlands to try at 4k (I know, not the game to stress test with)...forgot how much I enjoy it.