This is why I dropped out of school I guess...
No matter how I try to math out 3 plants times 3 clones each, I can't come out to "3 at a time" Actually sounds kinda like 12.... and even with up to 3 in veg for 3-4months... not small plants.
When you are a legal medical grower with a grow tent and a plant count limit of 6-12 plants, or just a guy who likes to have a joint here n there.... you don't have the means or need to grow out a dozen plants at once because theres a chance you 'might' find a killer good pheno.... Worse to only have 2-3 small personal plants just to find out both are males, and you just wasted 4-6 weeks.
Pheno hunting is gambling, and gambling is for those who have the currency to spare in the event of a loss.... Time, space, and plant counts matter to a lot of us growers.
Dropping out of school is never a good thing. Severely handicaps your future. Then again I come from a family where education was put in the forefront, not sure how I would feel if my family didn't instill those values.
Having said that, let's return to growing. In my response I assumed a few things:
1) the grower has some means maybe $100 spare cash a month.
2) the current grower is smoking something now, which was probably bought- so that should continue until that is found
3) when you clone they can take up to 2 weeks to root, in that time your current 3 plants in flower have shown their sex. Once you know which ones you want to keep you toss the clones from the male.
4) when it comes time to picking clones you choose the healthiest one from each cut. For example you took 3 cuts of plant A - you only keep the strongest clone.
4) so by the 3rd week of flowering you will have isolated your females, and killed off the males. In my experience you end up with 1 or 2 in flower and 1 or 2 clones for a total of 4 plants
If the grower is in a financial situation where no money is available and they are currently not smoking anything than your logic applies. If what I assumed is correct- which it probably is my method is the best. But it does require someone with the patience and determination to garden...and maybe a bit of math skills