One thing I've been curious about for a while now is exactly what sort of food goes into a three month emergency supply. I don't generally eat canned/preserved

One thing I've been curious about for a while now is exactly what sort of food goes into a three month emergency supply. I don't generally eat canned/preserved foods, so I can't just buy a three month supply of the food I usually eat, and my impression is that most canned food has best-by dates of a couple years; do you have to renew your emergency supply every few years?