tomhrxbfg: I just started using DD platform for over over 1 month now (started Oct31), and I have already purchased like 50 games (including some bundle games)... I can't imagine if this goes on how much I am going to spend even though I don't have time to play. Most of the games are cheap that's the reason I buy them, and I tried my best to resist by reading negative reviews, but sometimes it's just very hard.
Most of the following advice has already been given, but here's my own take on the matter:
As someone who's just discovering digital downloads as a major source of cheap games, the most important thing is to understand that there is
no urgency to buy anything. The download services are pretty good in
creating a sense of urgency by offering great discounts for very short times, but - contrary to games that are physically sold - the merchandise will never sell out. This means that every game that's on sale right now will be on sale again at some point in the future, possibly for a better price because it's then older. So the real question you want to ask yourself is: Do I want to actually play this game until it goes on sale again? If the answer is yes, buy it. If the answer is no, wait for the next sale.