I have a small amount of equipment to store in relation to what most of y'all have. That said, several years ago I'd saved up and built a 50x30 metal building with 12' roll up doors on each end to drive straight through and a 7' roll up door on one end. On each side I put 10' wide lean to's.

If I had it to do over again I'd make those lean to's as wide as I could....the best bang for the $ and easy to get to. Like most things I don't know until after I know.