My stockpile is steadily increasing so I definitely have enough for a few years - as I've said before, this is why the whole "PC gaming is rubbish there are no games that interest me anymore" tale of woe peddled by some visitors to this forum doesn't concern me.
My advice is probably don't buy SP games costing more than a fiver as they will likely fall in price, assuming they are on Steam or similar. It can be tempting to buy new games at a 'bargain' price but it only feels like a good deal because the game was recently costing north of £20. For example I bought Max Payne 3 for £15 in the Steam summer sale because I was a big fan of the first two games but realistically I should have waited a year or two for the price to come down. At least I've completed it, I suppose.
One advantage having a lot of games of course is that you can be quite fickle - just starting playing a game and if you don't like it early on, move on to something else. Then again, some might view that as a disadvantage because you just live in malaise wandering aimlessely between games that you never fully engage with.
To me, games are almost like collectibles (which is kinda bizarre as they tend to be digital these days), I get a sense of achievement/pleasure from 'building my stash' at a good price. For example I will see some olde games that were highly rated going very cheap, lets say under £3. But maybe they aren't 100% in my comfort zone in terms of genre - something like Jupiter: The Nexus Incident. I suspect that will just sit in my library untouched forever.
Anyway, if you'll excuse me, I have an appointment with Halo 2
