I feel you have to keep friendship out of business. Prevents hard feelings and lost friendships afterwards. When I used to do textile restoration as a career all "Jobs" were written up in my order book. A written quotation was provided with the cost of materials. Materials were paid up front. For long-term jobs, then progress payments were made for labour. In my Terms and Conditions, all jobs had to be paid in full before I released their item. If not, it was MINE. Luckily, this never happened. Afterwards, I gave them a receipt (never mess with the Inland Revenue!). Also, I was not responsible for anything that came framed. In addition, I reserved the right to take photographs of my work and use them for my portfolio and for teaching purposes.