Ask Is it better to charge a flat rate or bill by the hour for projects that tend to run long?

[Edward22]

I have noticed that some freelance projects take longer than expected, even when the plan looked simple at the start. Charging by the hour seems fair, but some clients prefer a fixed price so they know what they will pay. At the same time, flat rates can become a problem if the work keeps growing. It can be hard to decide which option protects your time and effort better. For long projects, how do you decide the best way to charge without losing money?