Depends on numerous factors including intelligence, reasoning ability, determination, perseverance, and of course which formula. The easy formulas shouldn't take more than 20-25 minutes to fully grasp, but something like FVDs will take a little longer.
Yeah I should add that if it takes you longer than we said it might take for anything, that doesn't mean you should just quit...keep at it, you'll probably get it eventually.
Yea, I gotta agree with Jimmy Yoshi. It depends what route you take. There is HSAK which you can learn in a heartbeat, but then FVD's really take a long time to master/ understand. It really is about reasoning ability, and logical thinking. If you something goes wrong, it does take a minute to fix, but you have to go through the steps of what happened, and did I miss anything. FVD's took me a while to understand, I learned them this summer and I still am not great at them. They sure do make nice coasters though...
So, my friend came up to me the other day and asked if I wanted a frozen banana, and I said no, but I want a normal banana later, so... yea.
Honestly, I never really grasped it. Sure, I can maneuver in it and figure it out by trial and error to design a thing or two, but it never really got into my brain I guess and I always had to re-think what I was about to do.
Took me about half an hour to understand FVDs, thanks to a great teacher!
Ofcourse, getting really good at it, is a completely different story, and it goes on zo infinity...