I've never rented a game, but that being said, I'm not really one to trade in games either.
The only game I ever traded in was the Bionicle PS2 game, because I wanted to get that and Gregory Horror Show as a 2 for £30 deal from GAME, but the latter wasn't in stock, so I got Deus Ex instead, and they said I could swap it if I want the following week, once they get a copy in for me.
I ended up finishing Bionicle 100% over a weekend, so I swapped that instead lol.
I prefer to own and keep physical games, in all honesty.