There is no real reason for halogen bulbs to fail frequently - however 1) if they get too hot, (that is a bulb that is too high a wattage for the appliance) they don't like it 2) poor quality bulbs 3) more likely there is a loose connection somewhere causing the bulb to flicker off and on - usually so fast that you don't actually notice it - so I'd go over all of the electrical connections and make sure the bulb is tight in its holder.
John
December 2007