I have a 6 month old MacBook air. I use it for my online business at least a few hours a day and don't have a wireless mouse so I click the trackpad a lot. Lately it isn't always working when I light tap with my finger. If I use the pad a lot does it break easy?
Is it possible something got stuck or is otherwise jamming the trackpad? Best bet may be to have genius bar take a look.
On older macbooks there was an physical adjustment you could make on the trackpack (open the case, remove some stuff, adjust screw). And we had a problem with the battery swelling which caused the trackpad to stop working (essentially prevented the "click" action, as it was pushing the trackpad up).