the magic 8 weeks

hi all, from all advice i’ve seen, it seems that spacing laser treatment 8 weeks apart is the optimum schedule for zapping follicles at the ‘right’ time in the growth cycle.
my question to someone who understands this more than i do: i am days away from being two months post my first Gentlelase treatment on underarms & bikini, so due for my next treatment. the thing is there’s not very much hair growing back. should i wait longer 'til there’s more there or get it done again now. any advice would be greatly appreciated. cheers, lollie