Pet food quantity - large package or small package?

I usually start out with a small package but once I see that my dog likes it and everything is in order, I buy a bigger package the next time I go out for dog food. Buying bigger packages are less costly than buying many small ones on a regular basis. When the big package is consumed, I usually get another small package of something new - perhaps a different flavor or a different brand. If my dog likes it, I buy a bigger package of the new food in order to save some money. The same is true with canned dog food. I buy one can first and if my dog likes it, I buy a dozen cans wholesale. I would like to buy more than a dozen to save more but canned dog food is expensive.