Discuss how much space you need.

The storage people should have a way to help you judge how large a space you need to rent. Some estimators will give you only a general idea. The best way is for you to get the storage company to agree to give you a larger or smaller unit if your needs change when you arrive.

If you can, box everything and accumulate it in one area and then measure the cubic feet including unboxed items before you sign up for your final storage unit. If you are having your things moved by a moving company, they will be able to tell you the cubic volume of your load. Then the storage company can advise you about the appropriate size of storage unit.

You still need to decide if you want isle-ways in your unit to allow better access to your stuff during the storage period. Very generally, because situations vary, you may need about 60 square feet of storage for each room in your home. This figure does not include any aisles and assumes you will stack your things 8' high.