Even if you discuss payment prior to any service, there is always the chance that an issue or situation will present itself which will effect what you will be paying. (or charging)

Of course the issue must be a clear one–made clear—an obvious one— with good reason to “adjust” billing.

The client and the person charging, both need to know this going in with regards to any situation, with any service oriented profession.

Flat fees are good- but all too often after putting in your time etc. a client might expect more than what they have paid for.

This makes for an even more delicate and often uncomfortable spot to be in.
Best is a starting point flat fee-

kinda like haircuts— 50.00 and up

what does that mean? well if you are still in my chair after 3 hours because you either;

a.) you keep changing your mind –and time is spent re cutting… several times in spite of our agreement of service— which we both “agreed” to during our consultation then you need to be charged accordingly—

b.)if during the consultation you did NOT inform me that you had 10 perms and 48 colors in the last six weeks- or you weren’t fully disclosing important info when asked; then when the situation DOES arise and it will- then you need pay the fees for THE EXTRA work and SERVICE!

that’s just me though…I could be wrong—