One more question :
Is it better to take 1 month labs and if I need more time than buy additional time or it is better to take straight 3 months from the start?
Really depends on how much of an issue the cost is to you and how deep you want to go into the topics within that time.
Given the amount of time you can dedicate to it, I'd go for 30 days to start with. After the 30 days are up you can work on any areas you need too without wasting lab time. After that you should have an idea of how much extra lab time you'll need. This approach is only going to cost you an additional $50 if you were to add an extra 30 days to the initial 30 days.
I won the PWB course here last year with 30 days lab time, I'd originally planned to do the course myself with 90 days lab time. However, having used the first 30 days, I'm swaying towards to just extending by 30 days rather than 60 days, and I can't nearly spend as much time a day as you can.
Without the pressure of the lab clock ticking down, I've been able to research some topics far more deeply than perhaps I would have done otherwise.
Have you seen this review?:
http://blog.g0tmi1k.com/2011/07/review-pentesting-with-backtrack-pwb.htmlWe all learn differently and do so at different speeds. Also we all have different background experience and not everyone can put in the same about of time. Having now completed the course, I would say if you want to "just pass" the course and can put a good couple of hours in each day then you could get away with doing 30 days - at a push. However, if you want to take your time, learn it and (try to) "do it all", I would recommend 60+ days in the lab. I started off with 30 days, with the hope of cramming it all in as I could spend 8+ hours a day on it. In the end, it took me a solid 30 days in the labs (not including any of the exercises before the lab work), so I ended up extending it by 15 days. If I was to do it again, I'd opt for 60 days and pace myself better.