I should start out by saying I didn't start buying these light bulbs for myself, but that my dad gave them to me as a gift one year for Christmas. You see every year for Christmas my brother and I each get a special gift just from my dad. Now it has turned into Bo and I get a gift and Sister in law and brother get a gift. We open this after all other presents and it is something that my dad has thought of and picked out himself. One year as little kids we got ball gloves and as a teenager I got a cordless phone. It is always special and a surprise, but as I have gotten older the items have turned more to items for the house, which is great. The first Christmas Bo and I were married my dad got us a 6 ft. ladder. At first we thought this could come in handy at some point. Now, I can't tell you how many times we have used it.
Sorry, I kind of got lost there. Now, back to the light bulbs. These light bulbs were expensive when they first came out so one year my dad gave me several for Christmas to help me get started in changing out my light bulbs. Since then I have changed out almost all of my light bulbs, and I think at this point I only have a few lights that don't use these bulbs. My dad help start me on the path to save energy. I have to admit I don't think they last as long as the packaging says, but I don't keep the stuff to send them back in for the grantee. Bo actually has a friend who has a spread sheet to keep track of his light bulbs and he has gotten many for free. I just don't think that is worth my time.
If you haven't I would suggest changing out your old light bulbs with these energy efficient one when your old ones die.