So, clipping it at 31 days like me is a complete waste. It got me high about the same amount holding my breath for 2 minutes would.
However around 6 weeks it will start getting you high, the high is real buzzy, all head, it can be pretty strong depending on the strain, but it goes away quick. Doesn't have the power it will later. 7 weeks is that much more stronger, but still nothing like waiting till it's done. If I only had a couple plants and my harvest needed to see me through a long time, I would try not to clip any, just so it will all be as strong as it can be. Or at least as nice as it can be. I've harvested a plant part at 7, 8, 9, 10 weeks, I think the 10 week was the 'strongest' but not the most enjoyable high. It's sweet spot was really just over 8 weeks. I wanted to see the difference in the smokes at the different times. My favorite was the 7 week stuff, as the rest was just too strong for me. I'm a bit of a lightweight. These days I like to harvest some early on purpose because I like having a stash of less strong, more up buzzy smoke on hand.
And no, the plant wont herm because you clip off a branch, or even two. It's only when you give it constant stress, or weird light mess ups. Or genetics sometimes, but that's another issue.