how many weeks for veg?

I'm planning on veg. my northern lights for 5 weeks total, check my 2nd grow log in Sig to see my progression, but is that too short to veg? I did way less time last, want to make sure I do things as close to 100% as possible.

IMO 4 weeks is a minimum anything over that is a bonus longer veg better = more growth end result more bud

i always say that if you have the room to go as tall as you want, veg the fuck out of your plants.. i usually like to veg till i see one of two things, if not both of them.. the first is alternating nodes.. once the nodes start to come out alternating, it means that the plant is getting ready to reach sexual maturity..
the second thing i look for is preflowers.. also i sign of sexual maturity..

i was told it like this.. you can always flower a two week old plant, but doing so is kind of the equivelant of a 12 year old girl having a baby.. all of the parts are there, and nothing will be wrong with the kid more then likely, but at the same time she won't be as well equipped as say a 22 year old lady having a kid.. no good job to help support the kid, more than likely, no loving partner, etc.. that always kind of made sense to me at least..
and i've read that flowering a plant before it shows preflowers will only end up stressing the plant out, and you won't get the best out of the plants.. this is why i can never understand why someone would want to do 12 / 12 from seed.. just seems kind of counter productive to me.. if there want to keep the plants short, there are much better ways of doing so than doing 12 /12.. sorry, i got a lil off topic, lol... but yah, veg them for as long as you'd like.. longer veg, bigger pots, bigger the yield will be at the end of the day, and who doesn't want lots of killer bud as opposed to lesser of the same quality bud??

12/12 from seed can be usefull when growing sativa dominant plants , I knew of a NL plant that was put on 12/12 by mistake, alls i can say is it ended up with 1 cola and no side branches i think it would of been perfect for sea of green , but I think i read somewhere that starting 12/12 can cause a plant to hermaphrodite ie have both male and female sexual organs so I agree that veg is important and with LST(low stress training) you can veg for 4 weeks and end up with a very bushy 1 foot plant http://www.gardenscure.com/420/training-scrog-sog-supercropping-etc/63090-low-stress-training-lst-more-walk.html

I am one that lets my babies root and stretch a little under florescent 24 on (rooting), probably a week or two more then most and then run a 4 to 6 week veg. I'm about plant size and health more then I am time line.