This might be biased as an experienced martial artist, but it wouldn't take me a month to figure out if I like it. 1-2 weeks of classes, and I'd know. And I'd feel guilty attending for the extra 3-4 weeks for free, knowing I'd planned on staying either way.
I agree. I'm of the opinion that an experienced Martial Artist can, in about fifteen minutes, know all he/she needs to know about a dojo from watching what's taking place.
As I've said before, I've been very fortunate. Had a guy come in that was friends with one of the students. He owned and ran a successful glass company. He watched a class and said to me "I'll make a deal with you. I'll mirror that entire wall for you, for free, in exchange for a lifetime membership."
It was an enormous wall, I jumped at the chance. He did a beautiful, high quality job of it. Trained for about a year, then got married and I never saw him again. Best deal I ever made.
On the flip side of that, had two guys come in, they watched a class. Afterwards they wanted to know what a lifetime membership would cost for the two of them. I asked them to take a month of classes, free, and we'd discuss it. They said they didn't need to, they knew what they liked. I explained to them that the class they watched was one of the easiest classes we've had in a year. They didn't care because they were athletes. (they apparently had no idea what an athlete was. Looking at them they looked like cupcakes.)
So I said. "Okay, I'll give the two of you a lifetime membership for three hundred bucks combined. We'll draw up a contract BUT when you quit in a month I'm not going to give you any of the three hundred back." They accepted.
Three weeks later they decided it was too much work for them, they wanted their money back. I said no. They said they'd sue.
Among the students that night were four long timers, three Attorneys and one Judge. I told them to go speak to one of them. They spoke to one of the Attorneys, then apologized and left.
The guy they spoke to asked them, "Do you own a house?" They said they did. He then asked them if he was going to have to paint the interior when he moved in because that's how long he was going to keep them in court."
It sure would have been easier if they just took a feee month of classes. And the way I always looked at it - if someone doesn't have the patience to watch multiple classes, they sure as hell ain't going to have the patience to train.
Last thing. We never advertised, or even thought of, "lifetime memberships." Clients brought the subject up. I thought of them as clients until they were there for a while, then as students.