Grandmaster- yes, my kids are young, but I tip them generously anyway. (If they deserve it!)
The Rebbeim of the younger grades also work very hard.
When the boys will get older, and I’ll be happy with their Rebbeim IY’H, I hope to give more.
ChanieE- that what I believe. But everyone should feel free to do what they understand is right.
(Yes, if the teacher would be 40 yrs old and her hub still in Kollel, I would give more.)