It is a crap shoot, like anything else. You just have to take the plunge.
It is kinda like locking in on a rate for a mortgage, if you have ever done that. You just wait and wait, thinking that you are going to get a better rate, and greed gets the better of ya! Suddenly it goes up a half point, and you know what happens then. Your mortgage payment is out of reach.
I got my airfare for Nov.28th through Dec. 5th about two months ago. It went down to $172.00 roundtrip, non-stop both ways and I didn't think it could go any lower, so I jumped on it. I told my dad the next day, and he asked me if I was sure I wasn't sitting on the wing - LOL.
My two friends got on the next day and it went up to $202.00. Still good.
We are almost 16 weeks out, and today, the plane is almost completely full and it is up to $350.00 round trip. I am glad I did it when I did!