if you rent a storage unit do you have to use their padlocks?

Normally you are allowed to select your own lock in using these facilities. For your convenience, the storage facility you use might offer locks.

Some users of these storage facilities would purchase cheap lock or one that do not fit the holes on the storage facility you would rent.

This is normally your choice, you might purchase one from an outside source or use one offered by the storage facility.

I hope this has been of some benefit to you, good luck.

"FIGHT ON"

I've used storage units over the years. Some where I could reach myself (first floor) and others that were lifted to different floors (that we users couldn't go up to, they brought the unit down to us at floor level) and all of them we used our own padlocks. They do sell the padlocks you can buy and keep. Remember not to put anything rubber in there (like bathmats) because a couple of months of heat will make them useless.

If they want to take responsibility for insuring all of your stuff against theft by their employees, you might consider allowing them to provide the locks. Otherwise, why on earth would anyone allow a total stranger to have 24-hour, unsupervised access to their possessions in storage?

Usually, your choice.

If they require you use their lock, then you do.