I've not been to a hairdresser for many years but always used to tip about 10% in cash.I always paid full bill in cash so just added a note, it was always my same hairdresser who charged it up at the till so it was a straightforward transaction.
Last year I started occasionally getting my brows shaped and lash extensions done (and no snide judging/comments about this please, this is just a question about tipping etiquette). It's a busy salon and you don't always see the same therapist each time, you just pay at the till when leaving but this is a cashier, not the person who did your lashes and it's card payments only.
I have never seen anyone tip and it's genuinely never crossed my mind - I never got anything like this done in my life until the last year or so! Tonight it just popped into my head though should I be tipping and I have a horrible feeling I should have been 
Do people tip for things like this, and if so, how much do you tip? There is no option to add a tip onto the card payment like there is in restaurants (and I always check this goes to staff if there is!) so it would have to be cash. If it's worked out at 10% ish that would be a mixture of coins and notes which seems awkward. Also, how would I do it - would I give it to the therapist after my treatment or give it to whoever takes the card payment?
Any advice gratefully received!