The Storenextdoor guide to self storage units 

Self storage units offer flexible, do-it-yourself storage i.e. the facility to store your items in a clean and secure, 24/7 monitored environment. You pay per size of unit for a set amount over a specified (or ongoing) time period. If you are moving abroad or moving home, or maybe doing building works or living in to rented accommodation it's a great way to store your household items.
For business customers, the access arrangements, security and convenience of self storage units (free parking, CCTV and pinpad access etc) are key to making it an attractive option. In addition many self storage companies offer specialist climate controlled and computer archive systems for document storage. 

Another feature of many self storage units is that the customer is the only key holder - the management of the facility are not able to access the unit. Popular unit sizes include:
  • 10x5 (10 feet wide by 5 feet (1.5 m) deep) which is about the size of a large walk-in cupboard
  • 10x10 (the size of a child's bedroom)
  • 10x20 (one-car garage)
  • 15x20 and 20x20 (two-car garage)

In terms of estimating how much space you need a rough guide (with the assumption you are putting all the furniture etc into storage) is:

  • 35-80 sqft for a 1 to 2 bedroom flat
  • 50-100 sqft for a 2 - 3 bedroom house
  • 100 - 250 for a larger 4 - 5 bedroom house 
The storage units are typically window-less, built out of corrugated metal, and locked using a padlock. A controlled access facility may employ security guards, CCTV, individual unit door alarms and some means of electronic gate access such as a keypad or swipe card.