It may be obvious advice, but I recommend changing the locks on your condo apartment or townhouse on the day of your possession. This applies to new homes, as well as to resale, and there's a specific reason for that. New condo-home builders often use a master key for all the suites, so that trades people can easily access a variety of suites where they're assigned to do work. Not only is your security later compromised because trades people might hold or have lost keys, but your new neighbours may all have keys that open your door as well as theirs!
The easiest thing is to have a mobile locksmith attend at the time you take possession. If you want to save some money, have a family member stay at your unsecured home while you take the door knobs and bolts to a locksmith, where they can be re-keyed and several new keys can be cut for a lot less than a home service call. While you're at it, consider re-keying your mailbox. Just open the box with the key you were given and the small lock can be unscrewed or unclipped from inside the mailbox door. Have several keys made, as mailbox locks can be expensive to have drilled out if you have no key at all.
Also consider upgrading the house or suite locks to high-security sets. If you've ever seen a locksmith "pick" a lock in two minutes, you'll never again feel secure behind a door with a standard cut-key lock. For an extra $60 to $100 per door there are high-quality locks that cannot be "picked", and for which the keys cannot be reproduced. No matter what quality of lock you buy or have re-keyed, match the door knob with the bolt, and front door with back, so that one key will open all your entrance locks. Make sure your property manager gets one of the new keys, so that an emergency issue such as a water leak while you're away can be addressed without having to break into your home. Also give at least one of your keys to a friend, so that if you're ever locked out, someone else can give you that backup key. Another backup option is to buy a secure keybox with a numeric code, so that you can leave house keys outdoors on your property and never again find yourself locked out.
For an added increment of condo home security, consider a secondary latch that can only be secured from inside. The old "chain" systems were good, but not very strong. Consider a spring-loaded latch that swings over the door, and anchored into the door frame with a "bolt buddy" set of braces. As well as adding strength against a kick-in attempt, this system means that while you're home and perhaps asleep, the door can't even be opened with those keys you gave to your property manager and to a friend.