Energy saving…

Bought an energy saving lightbulb recently, on which (plastic, hard to open) clam pack is written “15000 hours life expectancy”.

I can’t work my calculator because of the plaster on my index finger, put there courtesy of said clam pack, so I can only guess when I compare it to my life expectancy.

The resultant envelope maths leads me to the decision to leave the light on all day and night to get the anticipated value for money saving in paying four times more for said lightbulb than it’s replacement.