Bicycle racks should be installed using secure, tamper proof bolts and/or anchors.
Powder-coat finishes on racks are typically more durable means of maintaining a clear and aesthetic appearance. Finishes are also important to protect bikes against scratching. More durable but less attractive will be galvanized finishes that stand-up to wear and tear - thanks to Heath Maddox in San Francisco for the tip!
Rocks should be checked periodically to ensure bolts/anchors remain secure. "Coat hanger" cluster racks are sometimes vulnerable to vandalism or damage. The coat hanger elements are more easily twisted or bent than the rack frame.
Cage enclosures or wire lockers may be cut or damaged and need to be installed in more visible, secure areas to guard against vandalism. Bicycle rooms at workplaces or multi-unit residential buildings are preferred for this reason.*
Keys and/or card lock systems for residential or workplace bicycle parking will need to be periodically changed to mitigate against "leakage" of access/security.
Lockers, particularly those provided in open spaces where weather is a factor may suffer corrosion of locking mechanisms, which will need to be regularly serviced or replaced.
Security lighting should be resistant to tampering and damage and also be checked regularly for burnt-out lights.
* More robust perforated steel plate designs may be more expensive but offer more security.