The chicken or the egg? Red pill or blue pill? A 5×10 or a 10×10 storage unit? These are some of life’s most confounding questions. And while we may not be able to help you answer the first two, we can offer some smart strategies for selecting a self-storage unit that’s the right fit for your possessions and your situation.

What Are You Storing?

Before you can pin down how much space you’ll need, it helps to organize the items you’re putting into storage. Start by creating an inventory list of everything you’re storing and packing your smaller items into boxes, if you haven’t already done so.

Next, break out your measuring tape and write down the dimensions of all of your large objects and your boxes, said professional organizer Hazel Thornton, CEO of Organized for Life.

Decide how high your items will be stacked—if at all—and actually lay it out on paper, she suggested. Think of it as a game of 3-D Tetris, where the goal is to fit your possessions into the various unit sizes that a facility offers.

If you’re more of a hands-on person, you even can create a mock-up of how your boxes and items would be arranged in the unit, and then measure the height, width and depth of the large stack or mound you’ve created.

storage facility

Long-Term or Short-Term Storage?

In case you think this is all just a matter of playing Tetris and building forts, there’s another important factor to consider: the length of your rental term.

Thornton pointed to the example of a renter who’s in the middle of moving and needs her unit for just a few weeks while she’s between homes. Because this renter probably won’t require frequent access to her items, she can pack everything into a small unit without giving much thought to organization or accessibility, Thornton said.

Long-term renters, on the other hand, are more likely to repeatedly visit their storage units, especially if they’re storing seasonal decorations or inventory, Thornton said. These renters often benefit from choosing larger units that let them arrange items more carefully.

Attorney J. Kim Wright, a self-described “full-time nomad,” falls into this latter category. She uses a self-storage unit to house off-season clothing and other personal possessions, and she appreciates being able to easily locate certain items whenever she returns to the unit.

“I thought 
I needed a 5×5 storage unit, but the facility didn’t have one. I ended up
 with a 5×10, and I am so glad to have the extra space,” Wright said.

She noted that the additional square footage gives her plenty of room for shelves, a clothing rack and even an aisle.

Still Unsure?

If you don’t feel like wrestling with measuring tape or mock-ups, you always can go straight to the experts a storage facility for further guidance. Ask to view several empty units for an up-close view of exactly how much space each floor plan provides.

Also, a few online tools can help with your decision, said David Bakke, a writer for personal finance blog Money Crashers. Certain facilities recommend unit sizes that correspond with how many rooms worth of items you’re packing away. Some sites even provide detailed calculators that can estimate a unit size based on the exact number of possessions you’re storing (for example, three bookshelves, two bicycles, five life-size cutouts of Carrot Top and so forth).

“It takes the guesswork out of the equation,” Bakke said.

Even if you’re in a rush to reserve a storage unit, it pays to slow down and give your unit size careful consideration. Renters who skip this step could end up with units that can’t hold all their items or they might waste hundreds of dollars after reserving larger spaces than they actually need. Fortunately, you can avoid these issues by using one or more of these proven strategies to secure a unit that’s the perfect fit.