You asked: Why do my cake recipes with baking powder never work?

It seems as if every time a recipe calls for baking powder, I never get the rise I expect. I have made cakes and pound cakes that flopped with fresh-from-the-market baking powder, and they have been coming out barely an inch high. Is my oven too hot or cold? At $4.50 a can, it’s getting expensive buying new cans, all to no avail.