Slow or no?

My Mac Air gets bogged down while running - is losing my wifi - I often have to shut down and reboot. What do I need to do?

Not nearly enough detail there to make even a good guess, but you could start by providing some details on your MBA, including how much RAM it has, how much drive space is available, etc.

1. Have you done any maintenance on the machine? We recommend OnyX as a good free maintenance utility.

2. Do you actually QUIT programs you're not using (File->Quit or command Q) or just CLOSE programs (clicking little red button)? I'm going to guess the latter, and that could well be at the root of your problem. Not quitting programs properly means they are tying up RAM and other resources, bogging down the computer over time. If a reboot "fixes" the problem for a while, I'd bet dollars to doughnuts that is what's actually going on.