There is a lot of conversation about part time work picking up slack in bad sequence scenarios, so, Iím just going to point something out that may not be obvious. Someone retiring very young will likely still want to make a difference with their life. Sure a couple of years traveling, reclaiming mental health and physical fitness, working on the house or homestead, child rearing until kids become more independent will be fulfilling. However, over a period of decades this is not going to be enough for the type of person who was motivated enough to become FI.
Eventually, mentality will shift back to participating in meaningful activities. Unfortunately, most volunteer work is not that fulfilling in itself. Sure, you can stock at the food shelf two days a week, but this type of work will likely be no more fulfilling than working a 9-5 at the supermarket doing the same for 15 bucks an hour. Not saying someone doesnít have to do it, just that I doubt someone with a Mustachian personality type is going to limit him/herself to this type of activity. If you think a stocking volunteer who offers to create an inventory software and distribution system to increase efficiency will be allowed to do so, think again. If you want to make that contribution, youíll likely have to take a part time job at the food shelf, probably at a ridiculously low wage, but it's unexpected income. Want to volunteer in the medical corps for six monthsÖ sorry, but part of the package is that they pay for your food, housing and travel while on assignment, more unexpected compensation. I could go on ad nauseam, but the point is the world perceives value through how much they have to pay for it. Any truly meaningful activity is likely going to provide unexpected compensation.
This framework has been shown anecdotally, time and again, with the experiences of those on this forum. A 29 year old Mustachian who earns no other form of compensation through a 60+ year retirement is less likely than a 4% rule failure, and thatís pretty low.