memory question

[Sturatt]

can someone explain to me why more memory is better, when I never run out anyways? Why would having 50 mb free be better than having 15 free, until i reach the point where i have 0 free? I hope i am making sense... why is it better to have more FREE memory? I always see people talking about how the touch has more memory, but i always seem to have about 15 megs free, so does it make a difference until i actually need to use up that 15 megs?