My policy, which I pass on to clients, is simple - use wireless only where you can't use wire. Reasons:
- Security - most wireless installations are ad hoc and totally insecure.
- Performance - wireless doesn't get anywhere near the bit-rate advertised (overhead), is "shared media" rather than switched so its performance degrades rapidly as you add users, and it degrades rapidly from interference, particularly from other wireless devices.
- Eventually lawsuits will be filed by people concerned with the possible health effects of an environment flooded with microwave radiation.