Are you often at a job when your customer says “oh while you are here can you just do this for me?” It happens often, and more often than not when you try to charge your customer extra [for that additional work] they have something to say about it. Often you will find yourself in a wrangle to get paid, because the customer only wants to pay what you quoted. A simple solution is here. Be mindful of work you quoted for. If you have employees who do the grunt work, make sure they are armed with a copy of the quote and are knowledgeable about the work that is involved in the quote before they start the job. Train yourself and your employees to say “No worries Bill, but that is outside the quoted works so it will be extra, do you still want me to do it? Then, at the end of the day’s work or after you leave that job, text or email the customer to say “Hey Bill, just following up on our earlier conversation. You asked me to do X and I advised it would be extra. I’m confirming that gave me the go ahead to proceed, so I’m just letting you know there will be extra your invoice for the variation.” Pretty simple isn’t it? If Bill replies and says “No, I didn’t agree to that” then you do not do the extra work, but if Bill does not reply then it is taken as agreed and you can proceed with the extra work, and lawfully charge for the extra work. Your email or text then becomes a legally recognised diary notation of the conversation you had with Bill. This little process should help you to avoid disputes over variations.