I depends. Most of the stuff that I buy comes in dark pots...I only use clear pots. So I trash those that came with the plants.
If I am repotting something, I usually have to cut the pot to avoid damaging roots. If that happens, I toss the pot. If it looks to be re-usable, I clean and store it away for future use. I'm not at a point where I have orchids to give away or other stuff growing.