Most people I know with a self storage place are not using them like the article. (though some do - YMMV). Some use it as a warehouse for their business - they rotate stuff in and out. A carpenter might buy a pallet of nails once every few months and use the storage every few days to refill the truck. Several people keep off-season holiday decorations in storage and rotate it back home for the season. Others keep fishing stuff in storage and stop by storage on their way to/from the fishing spot.

If you have anything in storage you should look at it at least once a year to decide if it is worth saving. It is okay to say that "I love this thing from Grandma even though I don't have room for it", but you need to decide it is still worth it.