Another sign of the times. Record breaking RV sales. Difficulty at times/places to find a suitable RV park/campground without long planned reservations. And now the problem of affordable storage also.
I feel quite lucky. We have fenced storage available within the gated community where we live. $40 a month to store our RV.
Inexpensive, but nothing is perfect. There have been a few break ins and theft of small items from a couple of RVs. Mostly from the outside compartments.
The police tell us the culprits are typically homeless/drug addicts. And they say the commercial storage facilities are not that secure either. Things still disappear at those quite often also.
You take your chances, storing one anywhere these days.