Lotsa good advice I won't try to repeat, but it should be noted it took flyers years of pressure to get expirations more or less removed from most programs, so it's something to be cherished. I would definitely favor carriers with non-expiring miles, or at least lenient three-year "rolling" expirations. WN comes up short there. I've had 16,000+ "orphan" Korean Airlines miles sitting in my account since 1992 and I finally got a chance at a cheap and easy way to top it up to 25K. I plan to use that to take a vacation to Alaska on Delta.

It's important to concentrate earnings on as few programs as possible (ideally one) and tie in as many earning opportunities on the ground without buying stuff you aren't buying already (Pudding Guy and ValuMags notwithstanding). Do that and you might get something every 2-3 years, possibly more.

To really get in the "game," as was mentioned, you need the elite status and the mileage bonuses, especially gold or higher and 100% or more. Many of us don't have the business travel to support that, so we started doing weekend and other trips ("mileage runs") to top it up. I've been doing that for some 11 years now and qualifying status on exclusively leisure runs for most of it. I'll always try to make a trip of it, though, and stay at the destination and enjoy it for at least 2, preferably 3 days (longer if it's outside the 48 US).

I think at some point the bottom line is that you've got to love to travel. Either that or you get a lot of travel through your job (like it or not!) Absent those factors, a freebie every few years is OK for most people. I can easily see where they'd come to see some Flyertalkers as obsessive or otherwise dysfunctional, so I can only say the lifestyle isn't for everyone.