Is this accurate??? (flowering)

Of course the bigger the plant the more pot it will yield but I was told that when the plants get around 20-25in. tall is a good time to start the 12/12 light cycle. This accurate? When do you guys prefer to start flowering?

Most people flower their plants at around that height because they dont have the room or patience to veg a plant to 4' tall. I grow in my basement so I dont flower till there like 4 or 5 feet tall. I go big because I'm in no rush and have the room too.

some people veg when their plants are only one foot tall. I wait till at least a foot and a half. You are totally cool going to flower at this point, you have allowed enough growth to get multiple ounces off your largest plants. could get a QP depending on the strain, I guess.

lol....my tallest plant is around the 17in mark right now. However, for some ODD reason my plant is very very thin! When I say thin I mean its not bushy at all! Im kinda pissed about it, not sure if its crap weed or if my previous grow bulb (150w single incadescent bulb, hey im a newbie) is the reason why.

I plan on letting it get to about 20in and then start the 12/12 cycle even tho without it being bushy I assume I will get minimal bud, what do you think?

And yes I have updated my light system, im praying it has good results!