In 1983, I bought a computer sign maker that had just come on the market that cut pre-spaced numbers out of self adhesive vinyl. This kind of numbering system is perfect for mini-storage units. Testing has shown that the vinyl numbers last as long, or longer, than paint. We use only 3M Scotchcal premium material, which is the same material that is used on the outside of Air Force jets. NASA uses it on the space shuttle.
Auto makers use it for pin striping and graphics that withstand car washes and rough road abuse.
M has more money to spend on research than other vinyl manufacturers. They are the world leader in adhesive products. I cut numbers and used them at my own facility. Within two years, they were peeling up around the edges. I had to peel off all of that bad vinyl and it left an adhesive mess that had to be cleaned with a special adhesive remover.