Heck, yes! Check the S.P.A.M. (Sites for Points and Alternative Miles) Board here for ways to keep your account active, since your miles may be spread out among a few airlines. You also need to keep track of alliances. For a long time, if you flew Northwest or Delta or Continental, you could get credit in any of those 3 for flights on the other 2. So, even though you might take one flight on each airline in a year, you could get all of your credit in one program. (Check "Airline Partners" on each ariline's Web site.)

Years ago I signed up every time I took a new airline even though I flew infrequently because "you never know". My first mileage reward, in 1997, was a round trip ticket for my 12-year old son to go to a conference in Bermuda with me.