We too are "Self Insured". We took money from rebates, refunds, anything extra and saved it. Recently opened a Savings Account with it, even tho it pays next to nothing in interest, if we have a major expense money can be transferred to our checking to cover the cost.
So far in almost 10 years of "Most Timing" we haven't needed it, so we're way ahead of the game vs what we would have paid for extended warranties for that same period.
Michelle & Ann
2018 Chevy 3500HD Crew Cab High Country DRW, D/A, 2016 RW39MB, Dual ACs, Auto Level, Auto Sat Dish, Stack W/D, King Sleep #, 17.5" Sailuns w/Disc, MORryde IS & Pin, Comfort Ride Hitch, 5.5 Onan, Res Fridge & Induction Cook Top