A lot of being a frequent flyer is about attitude and behavior, besides miles. There are certain things you know, and certain ways you act, and when you start doing that, then you come more and more to fit the bill of a FF. For example, when you know you'll be standing by for flights, don't check luggage if you don't absolutely have to. Learn your airports to know the shortest lines. know the best seats. Know how to talk to and deal with TAs, GAs and FAs. Once you have these things covered, you are a FF. Most people that have greater than 30k/yr BIS are there, but there are some with a lot less that would also be classified as such.