I have a small increase annually. It's noted in my contract "Rates will increase each year in Xxxxxx."
Parents generally accept it (two exceptions in 30 years but I already knew they were jerks
)
Frankly, some years it does not increase my personal income because
a. Prices go up
b. I find new things I want to add in & it always costs something
But it's always nice to have a little more to work with.