In most cases people will charge 'rent' for these days, say $100-150 daily for the storage fee. 

I may need to Co-broker a deal in San Diego soon.......had a nephew sign with the Chargers.

Also is it even legal for me to charge rent for 3 years in advance after allowing the owner to stay in the property.

If I were to charge rent for those 20 days (or until the unit is filled), that would be greater than what I would charge for the repairs. 

If the dollar is destroyed, I charge rent in yuan, silver, gold, eggs or sea shells.

You may even be able, with two tenants, charge rent higher than your mortgage.  

the 2 kids bedrooms were on the same circuit so not only was a 1500 W heater, a radio , a TV and a light on that circuit but so was a new XBox ONE, charging remotes, two laptops, two phone chargers, another set of lights, a 42" TV and who knows what else.

PM calls me its cooold  tenant has new baby and cant pay rent and heat can you not charge rent for a few months so they can heat the house and then they will add it to the rest of the lease.. 

Battery charger, turn fridge on before trips, Dump station, Concierge parking service, Tire/Oil/etc check, Big drive ways, electric in each unit, etc.Canopy, I have seen in Texas.

Battery charger, turn fridge on before trips, Dump station, Concierge parking service, Tire/Oil/etc check, Big drive ways, electric in each unit, etc.Canopy, I have seen in Texas.