If you find that your infrared #lamps are just not lasting as long as they should you should try the following which will improve the performance. These are common occurrences in the commercial kitchen and mobile paint automotive environments.
Check that the cabling is connected correctly and that there are no lose wires.
Ensure that the cabling is of sufficient rating for the loading and temperatures
Cabling is is insulated to protect against sharp or hot objects.
Make sure that if the lamps are the push in type fit that they are seated correctly in the holders.
The lamps are not situated near vibration or where sudden sharp movements may occur.
Please feel free to add to this list if I have missed any to help other.