In addition to the first answer, life is shortened through excessive heat. Make sure enclosed ones have adequate space around them (by avoiding them being covered by fibreglass insulation for example).
I found they didn't last long in my place either tig. In my new house I have chosen light fittings that are not halogen, and without the need to keep so many different type bulbs stocked.
Hi tig. One particular fitting drove me nuts the amount and cost of bulbs it used. Now just have energy saving and 2-3 different wattages. Much better and I know I have the bulbs in the cupboard.