How often do you toss your makeup powders?

I'm looking for what other people practically do.

I know the industry recommendation is to dump your makeup every year or so, maybe less for liquids. And I do for liquids--foundation, mascara, etc--they get funky after a while.

But I have some face powders or blushes I might hold on to for over a year, and, in particular, I have an eye shadow pallet I've had for about three years now.

I don't blow on my makeup brushes to get rid of excessive powder, I just tap them on the side of my pallet (so less germ contamination) and wash the brushes regularly. I've never had an eye infection or any skin issues from my older makeup. I'm under the impression my powders are fine, but I'm looking for other opinions.

What do you ladies do?