I was at brunch recently with some friends of my girlfriend and someone asked what I do for fun. I mentioned that I recently took a trip just for the frequent flyer miles. They looked baffled and then asked if I was serious (legitimate question, I frequently use deadpan humor). I said I was serious and that I flew to Puerto Rico six times last year and never left the airport. I then proceed to explain my logic for mileage runs.
United 737's in Houston
It's not the destination that matters, but the number of miles accumulated. There are two types of miles, elite qualifying miles (EQM) and redeemable miles (RDM). Elite qualifying miles only count for status and reset every year. Redeemable miles are used for award travel and don't expire as long as your account is active. I enjoy 1K status on United because it gets me upgraded on 90%+ of my United flights and waves a number of fees (Three free checked bags at 70lbs each, free award ticket changes, free phone reservations, free same day confirmed flight changes, etc.). To attain this status, I need to fly 100,000 paid miles on United and their partners (US Airways mostly for me). Since my job doesn't have me traveling more than 30,000 miles a year, I need to make up the difference.
US Airways CRJ-900 at CLT
I close the gap by buying tickets. Home for Christmas, a trip to Long Beach for the Grand Prix, and a few other leisure trips doesn't get me much closer to 100,000 miles. To close the gap I need to fly just to acquire the EQM's I need. The destination doesn't matter, just time and money. For time, I don't want to take any PTO to do this, so I am stuck with Friday night, Saturday, and Sunday. Money factors in both the cost per EQM and hotels. Hotel stays tend to ruin the math, so I try to overnight in air. To find the lowest fares, I spend a good bit of time searching ITA Matrix. I like to find fares in the 5c -6c per EQM range. My Puerto Rico trips last year were about 3.8c per EQM so I booked every weekend last September. I'm less gung-ho on good, but not great deals.
United Airlines A320 at LGA
People still think you are crazy. No matter how rational your explanation, no matter how much the other person smiles and nods, they will still think you are crazy. It's ok. This game isn't for everyone, if it was you could never find an award seat or cheap fare.