Incremental feedback. How this works depends on the project. Instead of one multi-year project, it needs to be broken down into digestible chunks, at the end o

Incremental feedback. How this works depends on the project. Instead of one multi-year project, it needs to be broken down into digestible chunks, at the end of each you have to have a mechanism that tells you a simple 'yes, keep going' or 'no, you need to adjust'. I'd argue that this mechanism is almost always your end users. That feedback regenerates your interest periodically and will push you to keep working on the project. Without feedback, it's harder to justify your time and effort when interest starts to fade.