I don't normally use all of my makeup before it goes bad. Often I will buy things....like them for about 1 month...and then never use them again. The only things I ever finish are lipbalms because I use them constantly lol.
I totally depends on what type of make up it is and how well it lasts and can be stored. With almost anything powder I will keep until it is all gone. Same with most lipsticks. Foundations I will keep until they start looking clumpy, and same goes for and cream type products. I do tend to throw out stuff that I know I have not used in a really long time.
I only keep eye shadows until they are gone... never any fluids or stuff like that... if I see that it doesn't look like it did the first few months I bought it... then its out in the trash. Especially mascara... I don't keep those for more than 4 months.
I use mine till its all gone, most of the time, I have foundation that I dont even know how old it is, and Ive recently been using it as a base for eyeshadow I've had it atleast if my calculations are right 2-3 years
i always have so much stuff, and get tired of the old ones and move on to the next greatest thing that stuff doesnt have a chance to go empty on me! i've almost emptied a few powder compacts and mascaras
Is what I would be saying if I actually started taking note of how much money I spend and stoped looking for something else to buy when I just got something
....but I would....but, l almost always buy something else before I even get close to it going bad or running low....*sigh*
I have only used up a couple of eyeshadows completely, and I use liquid foundations and mascaras. New makeup comes out all the time, I almost hate to lose the chance to try something new! That gets expensive, though, so I have to control my impulses!