While it doesn't happen often, it does happen. You should consider having specific language in your contract about how living in storage units is prohibited. No matter how bad you may feel about a renter's situation, living in storage units can be dangerous and a huge liability to your business. Storage unit managers should routinely monitor the access logs, so they can see if it looks like someone is checking in and not checking out within a reasonable amount of time. Many storage unit managers also keep information such as what public services are available in the office to help those who may not have a place to sleep.