1 - Homeserve covers emergency temporary repairs ONLY. Those repairs may themselves necessitate higher costs when properly repaired. You may already have such cover under your house insurance.
2 - Boiler insurance comes down to odds. Probably not worth it whilst the boiler is 1-3yrs old, perhaps worth it year 4+ if your own diagonstic ability is limited and you can't get hold of a proper factory flowchart.
Car Warranty are a dangerous area. Certain car types are extraordinarily expensive to repair - any recent Common Rail Turbo Diesel can leave you with a bill for a new engine by a) design b) error c) mad diagnostics. Other "simpler" cars still leave you with the blown headgasket, damaged gearbox, top/bottom-end repair. Avoid automatics from anyone who doesn't know them well - they can be =A31500 repair plus fail again in short order. Many car supermarkets have hilarious terms & conditions like Carcraft; the warranty excludes normal wear & tear. Avoid particularly fancy cars from non-mainstream makes. Avoid popular small cars as they can be ridiculously overpriced compared to off-beat but reliable larger cars, where rust protection & components can be higher quality. Likewise the cost saving of super- whizzo engines can be negated by 1) servicing costs 2) failure costs
3) catastrophic cost.
There is a reason many companies lease vehicles 1) they get a deep discount because the private buyer subsidises the scale 2) if it really goes down the pan they have a means of exit 3) when they sell in 3 years the car has depreciated little compared to the price they pay. The private motorist bends over with a sign "Park Here" on their ass.
Honest John should be your first stop re car ownership re a) what to buy b) if you bought it what the risks are.
Boilers, well uk.d-i-y is as good a place as any. Drains, check your household insurance covers them - if not change to one that does.
Insurance is good for things like houses and things with single point of failure that is close to cost of new (TV panel, Laptop panel or mainboard/planar). Warranty is good for things like washing machines, hunt around for the free 3yr or 5yr deal. I'm astonished at what Argos/ Dixons/Comet get away with charging for warranty - but that's their business model.
Self insurance can be very effective, even 20/month or 30/month - you could have picked a commodities fund (broad, not just gold or oil), or emerging markets fund. After 3yrs you've enough for "Quite A Tooth Sucking Bill" :-) and since you accumulate monthly you even out the
+50% & -50% swings, ie, pick something very volatile that is not secular (Gold can be for example when the asset bubble does eventually pop). Alternatively pick things decorrelated such as a global equities fund at 20/month and global commodities fund at 20/month. Far better than paying =A35+8+12+20+18+42/month on various appliance, product, service insurance policies. Just keep it separate from everything else re "dip in" :-)