How many centimeters or inches does hair grow in one month?

Question

and is it true that the longer it gets, it grows slower?

Answer 1

I worked in a few hair salons as a receptionist and I remember the stylists saying hair grows something like a quarter inch every 6 weeks.

Answer 2

I've heard it grows about half an inch every month. You need to keep it trimmed though or it will break and it won't seem like it's growing.