"My name is Anthony. I've been figure painting for 40+ years...."
Some interesting answers here. For brevity, I don't really do WWII German stuff. Everything else is in play, as long as I like the figure.
For me, the point at where a stash starts getting out of control is when you develop varying interests. For example, there are only so many Victorian British Army figures out there. It is finite. If you throw in other periods it all expands exponentially...
Steve Bablefish is 100% right. If you fancy the figure then getting hold of one is better than kicking yourself afterwards.
Worse still - I bet we've all done this - is getting rid of a figure and then wishing you hadn't. I have two in mind for that!