Ok so when your pack says 9 weeks flowering do you take that as gospel and flower for 9 weeks or would you let it go longer or shorter if it looked ready or not
I certainly wouldn't use the breeders flowering time as gospel after day 1 of 12/12. I find waiting until actual pistils are popping out is the best way to go when it comes to counting down your days (and using it as a rough guideline)
You have to remember that some people flip a lot earlier than others. You have your SOG dudes who veg 2 weeks and flip. There's even a dedicated 12/12 from seed thread. People with the space and time to veg for a month or more.
The plant itself isn't going to start flowering until it's capable of doing so. Or mature enough anyways. Then there's a transition period.
I've had mature as hell plants that have been in veg for 2+months pushing out pistils and preflowers and going no further. They flipped right over and started flowering fast and didn't skip a beat. They were ready and waiting to flower. Then I've had short vegged plants that took a good 2 weeks of flip to even start pushing out preflowers and pistils.
Then there's also full flowering itself and tric color/maturity. Most breeders just state yes you can harvest in 55 days. Yes your buds could fatten up nicely by then and be frosty. But that frost could still be clear. If you prefer a mild effect then sure you could harvest then. Smoke a bowl and play some games or do whatever. Or you could wait until they've clouded over nicely and get rocked off your tits. Royal Queen actually states different effects in a lot of their flowering times (the first one that came to mind) As do a lot of others. Instead of Flowering time 55-60 days or late september it'll ready something like"You can get a respectable harvest in 55 days" it'll have that as well as a suggestion of letting the strain go another 2 weeks for higher potency, yield, flavors, colors or whatever. I actually find that quite nice because otherwise you're left going at it through trial and error. So harvest time is also factored by personal preference.
Growing an Indica and want to just toke up, eat pizza and play some COD? Sure harvest at 55 days. Wanna smoke a bowl then go to bed and sleep like a rock? Let that girl go another 2 weeks.