I think the op is concerned about all of the other fuses other than those in the fuse panel. Inline fuses in the battery compartment, front jacks for those of us with 5'ers, etc. There seem to be inline fuses everywhere.
I buy spares whenever I run across another one that I didn't have already.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof