Trading in games too soon.

When I buy a game I don't play it to completion right away. Sometimes it takes me up to a year to complete a game. Every month a new great game comes out and of course I want it. I find myself trading in recently released games, just to get the highest trade in value, before I even completed it. Then I end up buying the traded in game 6 months down the line again. When my brother and I go to the store and see a good deal, we always ask each other "Is the 3rd time you bought this game?" I know it is a huge waste of money.

I remember when the first Killzone came out for PS2, got it for christmas from my parents and I finished it a few days later.

Traded it in for another game around the start of January and always regretted doing so cause I wanted to play the game again. Ended up buying it again a few months later only to sell it again and then buy it again.