Personally, I've seen some guys give instruction to others that scare the hell out of me. Youtube turners are the worst. So I would do some club demos, and if someone asks you to help them, then it's right. Teaching, even free, opens you up to liability. And not just during the lesson. Anyone can make a legal claim that the lesson you taught them resulted in injury in their shop. When I taught at the local Woodcraft, a million dollar liability policy was required. When I figure any commissions or work in the shop, I charge $35/hr. It should be $50/hr, but in my area that price gets me no work at all.