I have a client who I completed a website for some time ago. Our contract well over, he still texts me small changes to be done to his site (for free). As a courtesy, I had been doing them from time to time after our contract was over. Finally, after too much time had passed to be considered small nitpicks, I had to say to him:
Me: If you think you would like to have me on retainer to do site work or support, you can purchase a maintenance package and I can take care of requests with priority. I have a lot of clients on the go that I have to respond to first
Client: No, just that link thing, I understand other clients have priority. If your tied up, you can just give me a time when we can revisit this.
Client: All I would like is that link.
Client: And the ability to do a gallery without the pictures looking wonky when I upload.
Client: And those spreadsheets I sent you inserted into the pages.
Client: Thanks, see the attached for the rest.