does the light schedule have to be precise?

im on a 12/12 now after veg for 3 weeks, and i doubt ive ever got it inbetween a 5min window period. a few times its been 15mins and its only halfway through flowering now. you think it matters?

15 mins late i mean, normally i turn off and on at 8, i can always turn it on on time, its just i tend to fall back to sleep at 8am to turn it off

oh ive done that for years, never use a timer, only plants that hermy has been one bagseed strain (hermy product)

im pretty much on time but sometimes off by more than what you mention.and i dont have the sligthest worry about 15-30 mins or more. also im bipolar and wether im awake at night or day, frequently changes and i make the ladies stay up with me, no problems. (turning the clock around for them)

Well its always better to be uber precise about it. Your plants wont die or anything.

Why not just set it at 8:15-8:15? Personally I just set my phone alarm 5 minutes before I'm supposed to get up and switch the lights on, lay in bed for 4 minutes, get up, turn lights on, get back in bed.

funnily enough i actually do!!!!! i tend to nod off in those 4min, like today, didnt turn off till 8.23am, well pissed off, i dont have enough plug sockets for a timer, u need two for the hps, im gonna set it to go off 1 min before i think, qiuck do it then back off to nodland!!!