48 weeks is such a wonderfully small number... But if the least little thing happens in the markets or whatever and the expectation is so high that magically 48 weeks is FIRE day, it's just asking for trouble in your emotional happiness in general and with reaching FIRE in particular. Here's a little trick on managing your own expectations... I used to manage IT projects and always marveled at how teams would put all their energy into a goal toward a specific date and then there was no emotion "left in the tank" for the "next day" when all hell broke loose with the bosses after issues occurred due to installation of software, changing organization, etc. Good bosses helped us expect the project to continue well beyond "D-Day" (aka, deployment day!)
Reality is you know your number. Then expect another year, expect a setback you didn't cause, expect the number to change a bit as you finalize your financial FIRE plan, whatever... Then laugh your ass off and be happy you worried when you retire in 48, 75 or 100+ weeks. Just assume the number is 100 weeks to undercommit and overdeliver to yourself!
