One of the worst things I've done was buying 3 bulbs in my house that use GU10 bulbs. What a waste of money, not to mention how painful it is to replace lightbulbs. These adapters are great if you're having trouble plugging them in (just like with lightbulbs, the adapter isn't to blame). When each GU10 burns out I replace it with one of these and use an LED bulb. The only reason I'm giving 4 stars instead of 5 is that I had a hard time screwing some adapters into the bulb, but with a little patience they worked.