OK not strictly FIRE but thought this might serve as a reminder that the benefits of Mustachianism start long before you reach that milestone. In my case having a good savings rate and FU money meant that when a good friend offered me the chance of a lifetime to crew his boat across the atlantic it wasn't a big deal to miss several weeks of income. Perhaps more importantly it gave me the confidence to be able tell my employer I was going to do it and would love to have a job to come back to, but if not thats ok I would sort something else out.
The trip itself was actually pretty cheap - accommodation is onboard and there's no restaurants in the middle of the ocean - and even flying my wife and daughter out to spend two weeks on the boat in the Caribbean when we arrived, and my air fare back, were covered by air miles from credit cards. Swimming in the middle of the ocean when we were becalmed, or watching the dolphins play in the bow wave were priceless!