You should choose where to store your furniture based on your needs. First you should decide on the location. If you are eventually moving within the area, you'll store your furniture near by. However, if you plan on moving out of state you will have to consider if you should store at your old location or the new. How often will you need to access your storage and where will you most likely be? Are you unsure what your final location will be?
Most moving companies can provide storage in their warehouses. Usually at a lower cost per square foot than self-storage companies. Many moving companies have affiliates in every state where your furniture can be stored. Also, movers provide minimal insurance coverage on storage lots, and you can purchase additional insurance directly from the mover for a fee. Transit insurance may continue coverage also. Storage lots are controlled by the mover, so you have more assurance that your goods will be stored in a safer environment, which is usually temperature controlled.
If you need to access your goods daily or weekly, you should choose a self-storage location. However, there are some draw backs to choosing self-storage. Your goods will not be insured by the self-storage company, you should purchase your own insurance to cover theft, fire, water damage, etc. Also you have no control on what will be stored in the units surrounding yours. Mice, insects or dangerous chemicals may invade your unit. Few self-storage units have heat or air conditioning, so be aware that many things you store could be effected by extreme temperatures.
You may also consider storing your goods with family or friends if they don't mind the inconvenience. Again if you need to access something, it may be difficult searching through stacked boxes and furniture, and you'll have to do it when it is convenient for them.
Moving companies storing your goods at their location will determine the amount of space needed. However, if you'll be storing at a mini-warehouse or self-storage, here are some suggestions on what size storage unit you'll need: 5 X 10 Unit- Holds a minimal amount: a couple of dressers a bed and 20 boxes, or a lawn mower, outdoor furniture and bikes. Good for storing seasonal items, college dorm items or outdoor items.
10 X 10 Unit- Holds about 2 rooms of furniture. Good for storing furniture from a small apartment
10 X 20 Unit- Holds furniture and appliances from a small house. Also, good for storing a car or small boat
10 X 40 Unit- Holds furniture, appliances and boxes from a large house. Also, good for smaller items allowing walking space between the items for easy access.