In the probably-quite-unlikely event that your project will last longer than you do – or at least lasts longer than your desire or ability to keep it alive – you’ll need to have a personal finishing line in mind.
When, ideally, will you let go of the project?
What state do you hope to leave it (what needs to happen so that you can leave without killing it?)
Under what circumstances will you leave before the ideal time?
What do you need to do and how do you need to frame your departure so that you and others feel good about you leaving?
Will it be a clean break, or are there ways you’d continue to support the project?
If things go wrong after you leave, what circumstances (if any) would drag you back?
Some projects get finished up and wrapped up neatly, others (often work serving people, like education or government) are by nature never finished.
If your project has no clear finish line, it’s worth considering making an artificial one. It could be after a defined length of time or based on contribution: after you’ve achieved a certain goal, had a defined impact… or if something doesn’t happen by a certain timeframe.
Your cause will rumble on (many of our best causes will do so for as long as there are people), but it’s naive (and unhelpful) to think that your project will last forever, at least in its current form.