How often do you guys change your nail polish colours, foundations and shampoo?
Re: Changes
I change my nail colours when they start to chip. I change my shampoo's when my hair becomes dry and frizzy or it changes. Don't really use foundation much tho.
Re: Changes
i change my nail polish colours mostly after a week.. shampoo until my hair starts falling out, and foundation .. just have one specific one i use 
the others make me look like i have all purpose flour spread all over my face 
Re: Changes
Shampoo: I try to switch after using 2-3 bottles of the same one.
Foundation: I have been using the same foundation for the last 4 years. Just started looking for a different one a few weeks ago. The ONLY reason I'm looking for a different one is b/c my "needs" have changed.
Nail Polish: I do my own nails at home and get sick of colors fast (plus they chip). Usually switch colors 1-2x/week.