The Bose QuietComfort line has been around since 2000. Since then it has evolved greatly into the QuietComfort 3, and QuietComfort 15. I had bought a pair of the QuietComfort 3 headphones back when they first came out in 2006, and have used them moderately for 6 years. At the time they sounded better, and had better noise cancelling technology than the QC2’s and I personally found them more comfortable. As the years went by (5 years), the ear cushions started to lose their comfort and the battery started to lose it’s ability to retain a charge as well. This was not a deal breaker, because both the ear cushions and battery is replaceable replaceable, but the headphones started to emit a high frequency sound whenever the ear cushions were to be compressed, so that I had to shelve them. These headphones are great from the short term to the mid term (1-4 years), but beyond that, the quality of the sound becomes strained and purchase of a new pair is advisable.