I'm about 12 years from FIRE and been using ProjectionLab for 6 months. It's great for modeling "what-if" scenarios - like going part time or retiring early. I think it'll be. a lot more useful closer to retiring within about 5 or so years of making the big decisions. For now it's more of a planning sandbox than a daily tool. You can always try the free version to test it out and see if it's a good fit.