I usually just say: There are 3 types of guarantees I could make you: 1. Guaranteed features 2. Guaranteed timeline 3. Guaranteed cost But you can only pic

I usually just say: There are 3 types of guarantees I could make you: 1. Guaranteed features 2. Guaranteed timeline 3. Guaranteed cost But you can only pick two! If they pick #1 and #3, then I charge per project, but they don't get the final quote until they agree on the full spec in excruciating detail. The build then takes as long as it takes. In my experience people choose this option 90% of the time. If they pick #1 and #2, then I charge hourly: and I work however many hours a day I need to, to guarantee the timeline and features. I don't really need them to agree to the spec in this situation, because scope-creep just means more billable hours every week. If they pick #2 and #3, then I charge per project, and I tell them to prioritize their feature-requests in order of importance. I build the project and add features in the order they requested, and when time runs out I turn the site on, regardless of how many features are done. In this way, I'm technically charging per project, but it's really just my hourly rate multiplied by the capped number of hours.