The thing is with pet insurance, is that a lot of the cover is very basic and doesnt cover things like theft, death or accidents.
Also, most companies only offer 'rolling' policies which have to be renewed every year. In that year, if your cat is diagnosed with an illness, the following year you renew, telling them about the illness even if it has cleared up, but if the same condition returns the insurance company will not cover it, as it is classed as a pre-exisiting condition.
The only way to get around this is to take a policy offering lifetime cover. I use
Pet insurance for cats and dogs from Petguard