Changing the locks is a common practice in the long-term rental market. However, in the corporate housing market, where rental turnover is quick, it is not very cost-effective to change out the door locks regularly.
Another landlord told me she had a dead-bolt built on the interior side of the door. She simply advises each new tenant to use the deadbolt when they are home as a surefire-method to prevent any unwanted entries.
For the newer condominium complexes, tenants can be reassured by the visibility of security cameras, an on-site 24-hour concierge desk and most importantly, secured entry points that usually require a key fob. The homeowner associations will usually issue a limited number of key fobs to each owner and additional requests come at a hefty price tag at upwards of $50.