When choosing a professional locksmith, or other security technician, you should use due diligence to ascertain that they are reputable and qualified. This person or company is going to have complete access to your property and possessions.
If they are making new keys, installing new locks, a CCTV system, an access control system, an alarm system, a safe or other security device, you need to be assured that they will turn over all keys or credentials when the job is finished. If they are keeping records of any part of your system, they should make you aware of what they are keeping and why, and assure your that the information is secure.
You should determine if there are any legal or regulatory requirements in your State or Province, and if so, are they in compliance. Licensing for locksmiths is not required in most states. You may wish to ask neighbors or other businesses for recommendations, you may want to check with the Better Business Bureau the local Chamber of Commerce, or your local Police Department for any complaints.
You should be sure that they are insured and/or bonded and that they have all required business licenses or permits.
See if they belong to local or national trade associations, this may not always be an indicator of competence, however if they are members of these associations, they are more readily exposed to new products and new developments in the industry. They may also be certified at some level by these associations, again certification may not guarantee their level of expertise, but does show that they at least went through certain classes or training in order to attain that certification.
A well stocked retail store is a clue that should not be overlooked, however many very successful, competent, security professional have their shops in industrial parks, or just run mobile units. In some smaller communities it is not economically feasible to have a retail store.