Newbie AG/Grow Question

I just bought an AG Deluxe and will be using this for personal use only. I have never grown anything so I'm a little clueless, I've researched this forum and I don't think anyone else has asked this, so I will. If someone has asked this question, please direct me to that post and then delete this one. Thanks in advance...

What prevents me from getting a couple 2 or 3 months into my grow, cutting off the tops and then using that as my stash. As I run out, keep chopping. Based on the growth rates it seems like I could have a constant supply without having to keep buying.

Is there some reason I have to harvest it all at one time? Is it the root system, would it get too large?

They won't have reached maturity, so won't be as potent, although towards the end, yes a progressive harvest can be done, but the planr will still need to be totally harvested eventually .

I guess the closest I can explain what I'm talking about is what a salamander does, regenerating and all. Does weed regenerate?

Damn, if this grow is anywhere near as good as this bag, I'm a happy dude!