Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Not the upgrade I had hoped and they didn't last long

Several years ago when I replaced the headlights in my 2008 Chevy Impala with these bulbs it made a 100% difference and I was impressed. When I recently replaced the factory bulbs of my 2010 Mazda CX-7 with these bulbs, the difference was only marginally noticeable. It may be that the factory bulbs of the CX-7 were better than those of my Impala or it may be that my expectations were higher this time around. Either way, the difference was not really worth the cost of upgrade and to top it off, both bulbs died w/in a week of each other only 5 months after installation. The improvement was barely noticeable and probably not worth the price of the "upgrade" but the fact that they only lasted 5 months makes me wish I had not made this purchase.