Before I got heavy into PC gaming, I would save up for games and only buy them new, at full price, if I knew for sure that I really wanted to play it. This was probably about once every few months. Now that I mainly play games on my PC, I buy them a lot more frequently - maybe once or twice a month at least. This is especially due to the frequency of Steam sales, where I always end up making impulsive purchases no matter how much I tell myself I'll probably play the game once and forget about it.