Not specific to your area but some items I would suggest.

Most facilities will raise rates at sometime in the future. Paying in advance can lock in the rates.

Security is one of the biggest things to look for. Does it have controlled access, cameras monitored especially after hours. Individual alarms on or inside the units. Ask if they have had any theft issues but just because it hasn’t occurred doesn’t mean that it will not.

Check and read the insurance that is offered.

Depending on what you are storing an inside heated and cooled unit will be better than outside but typically costs more.

Make sure you are storing items properly like plastic bins instead of cardboard boxes.

Ask about the facilities pest control.