When looking for a new commercial space, the actual floor space that you get is important. Not only may it define how you set up your business, but you look at the rent through the lens of what you pay per square foot.
This can get tricky, though. Landlords and tenants may not have the same thing in mind when talking about "rentable space." In fact, some experts warn that most leases really only give you access to 75% to 90% of the area that is listed in that lease.