Simple - being incandescent bulbs, the brighter they are, the hotter they get. As Nightbeakers are pretty bright, they get pretty hot so don't last as long.
If yours have been in 3.5 years, you'll be surprised if you renew them and see how much brighter the new ones are!
__________________
Cheers
Dave
Next Door to Top-Gun with a Honda CR-V & S Type Jag  Volvo gone but not forgotten........
|