I can see a place for carrying large loans after FIRE. If I can get my roof replaced with a zero percent loan, or even up to 3.5%, as long as my investments are piling up at even a slightly faster rate, the only problem I can see is that an emergency might necessitate another large loan which would begin to cut into capital. That's a calculated risk, and has to be judged on a case-by-case basis.
If I understand the Mustachian philosophy correctly, it's to live well, within your passive income. Like the man said about yachts, if you have to ask about the mileage they get, you can't afford one. Affordability being defined as an expense that does not cut into capital, thus requiring a diminishment in lifestyle.
So emergencies aside, a large loan with a small interest rate might in some cases improve the FIRE lifestyle. Any comments?