In reply to SARS: I've been fingerboarding for just under a year, mostly I haven't done structured training, but I use it a lot - every day essentially.
My bouldering grade has gone up immensely in the last year, and although I don't know how much that has to do with fingerboarding, it's definitely got something to do with it. (did my first font 7a this time last year. Did a font 7c by April and am doing a couple new 7a/+'s every session)
I took a few months off climbing this summer (by necessity!). I noticed when I got home, I couldn't hang onto the fingerboard at all, just the biggest holds of a Beastmaker 2000. Within a week I was back almost to full strength. I reckon I was almost as strong as 3 months previously, but I'd forgotten how to hold onto tiny edges. Once I'd calibrated what felt 'right' again, it was back to business as usual.
Anyway I'm going on. Hard question!