If it's something that isn't standard or I know is so peculiar to me (mechanical keyboard, expensive mouse, headphones) that the company can't redistribute it when I leave, I just buy it myself and bring it in.

That slippery slope is also slippery on the other end, ok, company A bought you "xyz gamer laptop" when everyone uses MBPs or what not. 99% chance it's going to go sit in the closet for a few years after you leave until donated or sold whereas if you used the standard equipment it can be cleaned and released.

I'd rather skip the hassle and bring my own things in if it's not a change to the standards.