I would also point out that a few of us are maintaining gold or even platinum status on 100% leisure travel. In my own case I've been gold or higher for 15 years straight at about 97% on my own dime (100% since 1996). Most earning is on shorter (3-4 day) domestic trips wherever the best deals go, hopefully with free upgrades (which is why I'm with NW). Can't bring myself to do pure MRs; you have to really like to travel. Have gotten to all 50 states. Miles have been spent on longer international trips (am a free-travel person rather than an upgrade person).

If you can get your work hours under control and a flexible schedule, the advantage to this approach is that you're in control. Take or turn down deals as you like and have 100% of the time in the destination to do as you want. The disadvantage is you have to pay for it, but you'd be amazed what you can do with 2-3* Priceline hotel bids or coupon-stacked car rents that rack up points in the car-rent loyalty program. You won't likely get the extra benefits from playing the hotel programs or from what airlines give for Y fares or international business, but you can still earn and burn very well if you stay in the elite game.

With biz travel, a few get too much and most get very little; there doesn't seem to be a happy medium. Corporate travel departments have to use directives as a blunt instrument (individuals have much more flexibility). For every business traveler who gets a changing selection of glamour destinations there are several that have to earn miles by covering regions or traveling to the same worksites (like company plants in Peoria or banks in New York) over and over. It builds miles and the travelers understandably insist on perks, but it isn't everyone's idea of fun. I say this not to be discouraging, but to give a more realistic picture of what it's like.