Self-storage units are available for both short and long-term renting. If you wish to keep your belongings in storage for months or even years, you need to be deliberate with your choice of storage unit and how you pack, among other things. For the best outcome, here are some great tips to keep in mind when renting self-storage units for long-term storage. 1. Pick the Right Unit Assess what you want to keep to inform the right size of storage unit to choose.