I have operated a web business for 6 years now, and a few clients of my company could be considered "small local clients". If you enter into an agreement to do work for these types of clients, you have to understand that they're likely to see it through the lens of a long-term relationship regardless of if you see it that way. They WILL call you post-launch for help, they will be reaching out to you for months and years to come to help them out with various tasks related to their site.

Knowing this, it's important to establish to the client from the beginning what your role will be post-launch. I have turned this into a lucrative source of (largely) passive income as I require clients to agree to at least a year of contracted monthly support. My contract is structured so that they owe the fee every month, regardless of whether they reach out for support or not. If you're thinking that most clients would never agree to this, I've yet to have a client that didn't. And the reality is most of the time they don't call for support, but the appreciate knowing that they can if something comes up.

This is a win-win, they get the peace of mind knowing that they have someone who will help then when they need it, and you turn that into a stream of (largely) passive income. (This works for large clients too of course).