Halogen bulbs can be weakened or damaged by the the oils on your skin and many other contaminates, it is important to only handle halogen bulbs while wearing clean, disposable gloves. Keep bulbs in the original packaging until use.
If you do accidentally touch or otherwise dirty a bulb, it's best to clean using light solvent such as alcohol and a clean, lint free rag.
Regularly check bulbs for debris or buildup, some print media can stick to bulbs shortening life. When changing bulbs, check ceramic socket and contact for damage or corrosion, clean or replace if necessary.
Halogen bulbs are very sensitive to changes in voltage. Be aware of the effects this can have on bulb life.
Contact cleaners remove dirt, dust and oil from electrical contacts and have no flash point. Rubbing alcohol is safe to use on quartz tube of lamp.
Replace bulbs when damaged, burnt out, or they become excessively cloudy. Always replace bulbs with those of proper voltage and wattage.