As with most insurance it is a case of paying for something you might never need. I had a few quotes when I purchased a new car but then thought do I really need to pay extra? yes if anything should happen you are covered but again if you are a careful driver would anything happen? I know you have to be careful of everyone else around you but for this reason I did not take it out, at the moment just under a year of happy non accident motoring with this new car
I've gone with ALA for my Prius Plug-in - 2 reasons being the product they offer - 5 yrs cover, and its vehicle replacement, with the car I've got being rather specialist, I suspect the next generation will be a good few grand more to buy the same equivalent car in a few years time, so they'll basically pay up to a £17.5k short fall and put me in a 9 month old Prius plug in (which is the age mine was when I brought it), rather than return to invoice which could leave me short.
Was only about £240 as well. Equivalent of £4/£5 a month, which isn't bad really imo.
Its all personal choice though, I've never had it before, but then again I'd never spent quite this much on a car before.