This is a guest post by Beeminder user Jill Renaud.
I hate my current gym. It is a budget gym with no classes, machines in disrepair, and the other members can be downright rude. I can be patiently waiting for a machine and be cut off by a gym rat. A literal rat. (Kidding. It’s not quite that bad.) So I visited a much nicer gym and want to join. The gym has two main membership options: month to month, with no contract, at a cost of $75 per month; or a longer-term contract (1 year for $750, 2 years for $1200, or 3 years for $1500). Assuming that I will actually use the gym membership for the duration of the contract, it makes the most financial sense to buy a long term contract. The three-year membership is the most economical, working out to $41.67 per month, which would save $1125 compared to buying month-to-month.
The savings are predicated on the assumption that you actually consistently use the gym.
Of course, gyms know that actual attendance — especially over the course of years — doesn’t always align with the good intentions you had when you were signing up and they make a killing by offering these sorts of contract “savings” because the savings are predicated on the assumption that you actually consistently use the gym over the entire contract period. So how can I ensure consistent use of the gym? Beemind it of course. ;) 
One of the main reasons that I want to join this gym is for the fitness classes. I have found that historically I have no problem doing cardio. I’m the typical female cardio queen at the gym: I am naturally inclined towards cycling, walking, jogging, using the elliptical, etc., but I cannot compel myself to pick up a weight. A membership at this gym allows me to attend several free weightlifting/resistance classes, which I need, but I cannot take these classes if I am not a member of the gym. I value these classes at about $10 per class so if I attend 4.17 classes per month (approximately 1 per week) then I would break even with the $41.67/month membership. If I attend a resistance-type class twice a week then it’s a great deal and I think that is reasonable to expect of myself in order to get in shape.
Building in a safety buffer, I have decided that 1.8 classes per week (9 every 5 weeks) would still be cost-efficient and help me meet my fitness goals.
Of course, for a Beeminder road to be successful, I must feel that it is high-stakes enough to force me to reach my goal. I have decided, arbitrarily, to risk $1125, which is the amount that the three-year membership saves me over the course of the gym membership contract. As it goes with Beeminder contracts this means that I will have to pay out $1125 to the owner of the contract if I ever go below my Yellow Brick Road:
Now the question becomes: who is the lucky winner of my contract? (Bids are welcome in the comments. Read the fine print.)
UPDATE: Ed Fu has won Jill’s contract for $40. Congratulations to Ed and good luck to Jill!
UPDATE 2011-08-20: Jill and Ed got married! This may not bode well for the motivational power of Jill’s gym contract but it bodes very well for Jill and Ed!
UPDATE 2012-09-28 from Jill: I’m now 1.5 years into my 3-year goal but nowhere near the numerical halfway mark. I’ve had a lot of flat spots on my road because of various life events — marriage, moving to a new place, living 3000 miles away from my spouse for a few months, and perhaps a bit of laziness mixed in. I should be at 141 workouts right now, but I am only at 123. I am redoubling my efforts so that by the end of my gym contract I will hit the 281 workouts that I need to satisfy my goal. And, yes, having your husband own your contract when money is shared isn’t necessarily the best idea. The current Beeminder implementation of Danny and Bethany taking your money is much more motivating. :-)
Further Reading (from the Beeminder staff)
- A study on naivete and projection bias in gym memberships. And another by the same authors, focusing on a field experiment.
- Another study on incentives to exercise.
- Here’s a company that hopes to build contracts like Jill’s directly into your gym membership contract: Gym-pact.
- Our article on akrasia and the philosophy behind this kind of commitment contract: How to Do What You Want.
 The Beeminder folks would like to point out that this sort of thing, more generally, is a great use for Beeminder: insurance against wasting money on gym memberships or fancy treadmills. If you’re going to spend $1000 on a treadmill, hoping you’re not one of the 40% of people who will use it as a clothes rack, why not make it $2000 and pretty much guarantee that you’ll actually use it? (Plus get $1000 cash back!)