I view it the same as boiler insurance - instead of paying £15 a month£15 quid a month would probably be quite good value if it not only covered breakdowns, but the cost of a new boiler when needed. But most maintenance contracts don't include the cost of a new boiler when eventually needed.
> to insure the boiler, save the money in an account and when the boiler
> needs replacing, buy one and get it fitted with the money saved