One thing that may deter people from renting a self-storage unit is the belief that all units are the same size. Indeed, if you were to drive past a storage facility you may find that all the unit doors appear uniform. If you have surplus to storage but feel you may spend too much on wasted space, you may be reluctant to rent. In truth, reputable storage facilities offer units in a variety of sizes. Some are smaller than others and priced accordingly, and if you have a good grasp on what you plan to store you can find the right-sized space.
Before you hand over your credit card and assume a monthly payment, however, there are steps you need to take:
Assess exactly what is going into storage and put it all together in one space. You may want to take a picture or two and measure the mass so you will have an idea of the type of space you need.
Compile a list of local storage facilities and research pricing and available units. You might find that while the business closest to you is a simple commute, another facility may be less expensive and offer better perks. Take everything into consideration when you make your choice.
One thing to consider when renting units, especially smaller spaces, is ceiling height. Some units may be considered more like crawl spaces where you only have so much room to fit your belongings, while larger units allow you to stack boxes up to nine feet. As you research your options, take note of dimensions and adjust your stuff as necessary to make sure everything fits.
For a quick rule of thumb guide to storage, here follows a listing of the more common unit sizes and what they typically hold:
Small 5x5x4 or x6 (about 25 square feet) – A unit this small could hold to up 35 standard file boxes, or a combination of boxes and a chair and/or table. Watch the ceilings!
Small 5×10 (about 50 square feet) – You can put as many as 50 file boxes in this space, or a selection of small furniture, a sofa or shelving, or bicycles.
Small to Medium 5×15 (about 75 square feet) – This unit will be longer, allowing you to store a sofa and some larger furniture. You can also stow away bicycles or a motorcycle.
Medium 10×10 (about 100 – 150 square feet) – If you need to stow the contents of an entire room, this size may be right for you.
Large 10 x 20 (200 square feet) – This is the size of a one car garage.
Extra Large 20 x 20 (400 square feet and larger) – This can hold an entire home’s worth of furniture or the inventory of a small business
Some facilities offer larger units that let you store a car or a boat if necessary. If you don’t need that much space, however, research smaller spaces and find the best deal.

Article Source: http://EzineArticles.com/?expert=Kathryn_Lively

Bast Storage offers over 60 different unit sizes for your convenience, so you do not feel like you are paying for extra space. The walls on our units are 10ft high so there is plenty of room to stack. We offer units for personal effects, vendors, as well as vehicle spaces.

Because most climate controlled storage units are located indoors, there is less chance of outside vermin and pests infiltrating them. Damaging insects such as termites are kept at bay through concrete and metal construction. Unregulated units may become susceptible to outdoor pests such as bees, wasps or mice if not inspected regularly.

Many renters believe that peace of mind is also an advantage. Precious family heirlooms, antiques and other valuable items may or may not survive long-term storage in regular storage units. With a climate controlled storage unit, there is much less chance of discovering significant damage to weather-sensitive items.

Another advantage is atmospheric regulation. Items stored in these units should not face extremes in air temperatures or humidity. Many wood-based furniture pieces, musical instruments and antiques could crack or split from a constant cycle of freezing and thawing. Many storage unit facilities use indirect heating and cooling systems to maintain air temperature, rather than individual heaters or air conditioners in each unit.

Quotings from http://www.wisegeek.com/what-are-the-advantages-of-climate-controlled-storage.htm

Our units are protected by SonEquity Pest Management (http://sonequitypest.com/) which has been serving our area since 1998. They keep our units free from every type of pest, which is a major benefit compared to an outside storage facility that can be overrun by pests such as mice, ants, wasps, etc without proper routine inspections.  Since our storage facilities are located inside of a concrete and steel warehouse termite worries are virtually non-existent. Our units are managed for pest control on a monthly basis decreasing the chances of any pests being in the facility.

Bast also keeps the units at a constant temperature around 70 degrees so your valuables are safe from cold and extreme heat.