Should I tip a groomer? (belly, main, Himalayan)

[Caligula1]

I'm bringing in a cat for a summer shave tomorrow, she's getting a lion cut..
The main reason for doing this is she's been very resistant to allowing me to brush her belly and she's starting to get knotted..

She's a flame point Himalayan and her fur is like cotton, I cant have her getting matted underneath..
She used to be ok with brushing on her belly but lately it's been a battle and I'm tired of getting the battle scars..

So do I tip the groomer?

[CrowGirl]

I always tip my groomer. I have no idea how common it is, but I do.