I have just sat the November plumbing exam & thought it was pretty fair, i would go even as far as to say pretty easy, certainly compared with some of the other past papers that i have been trawling through for the last three months or so.  I did attended a night registration class for 10 weeks proir to the exam & i estimate 80 hours of study. My opinion is that was just the right amount of study and the level to which that got me to makes me 95 percent certain that i have passed. Some of the marks were absolute give aways, for example you got 1 mark for working out 70 minus 20 & 45 minus 20. I sat the June exam & failed that one, i would estimate i put in 20 hours of study last time which obviously wasn't enough. If i can offer a tip to anyone from my experience it is this: There is no point fighting the fact that you have to go through the whole process, accept it & try to enjoy the new knowledge you are gaining, some of really is fascinating stuff. You turn into a nerd for a while but it'll all be worth it, i hope!