That is very difficult to answer because there are so many variables. Hardwood vs softwood as well as plywood and the type of glue used in the plywood. I look for burning, fuzziness and quality of cut
Gotcha, i just saw that you had 4 1/8 up cut and straight bits so was not sure if they broke/dulled quicker then most
The only bits that I have broke was a couple of 1/16 bits and 1/32 bits. I have never had an 1/8 bit break
I also just started to buy the downcut bits. When cutting plywood these work better and help cut down on the fuzziness
Whiteside bits have lasted about 200 hours on average
That turned out great! I am sure she will love it.