1. do not buy any extended warranty
2. pay for any repairs out of own pocket
In my experience, the sum of money saved in #1 will be several times larger than anything paid out in #2, over the course of any person's driving or riding experience
Insurance companies would not underwrite extended warranties if they did not make a load of cash from them.
As an example, from 2018 to now, an extended warranty for each of my BMW bikes would cost £350 a year, each. £700 x 4 = £2800. In that time, I have paid absolutely zero in repairs that were not routine maintenance.
If I do similar maths for other vehicles since starting to drive in 1980 the figures become quite large but I have been lucky and I have not had anything major fail on a vehicle I have owned. If I do get a major failure in the future then I will just take it on the chin and cough up, or break the vehicle for parts. Overall, I would still be quids in if that happened to both bikes and my little hatchback car.
If anyone is worried about having a major expense on a vehicle they should open a savings account and put £40 a month in the account for every month they own a vehicle. Draw down cash as needed for repairs. By the time they stop owning vehicles, I am pretty confident they will have a nice nest egg. This would be a more precise form of self underwriting rather than my notional effort.
+1 and I've always done this.

