Yeah, they can certainly be timesinks. I usually go for a ton of short games and then a super long RPG whenever possible. I try to finish at least one epic RPG per year and when I start one it can last me for months.

It's the best way to get your money's worth, that's for sure. But it's not something I want play all the time, so some short games in between to spice things up will do the trick. :)