I HATE bloody halogen spot light bulbs. They last about 3 weeks meaning out of 12 in our bathroom/kitchen etc we very quickly get down to having minimal lighting before I nag someone tall to change them 
Whilst planning a new bathroom, the chap said we could have some light bulbs that last a guaranteed SEVEN YEARS!!
this absolutely delights me 
The bathroom chap was talking as if we would need to rip out the old halogen spot fittings and replace them, but then a quick google brought me these LED light bulbs.
So can I just replace all our existing halogen spots with these LEDs? or do they need completely different fittings?