You need to be careful when deciding which Home Warranty Company to sign up with. It is not just price. One thing I found in the small print of one Home Owners Warranty Company was a depreciation schedule. Any item older than the age that was posted on their schedule was not covered....
George
Also check the rate of depreciation. When we bought our house last year, one of the ones we looked at had a depreciation schedule buried in the fine print (not in the marketing material) which stated <paraphrasing> everything takes a 50% hit after year one.
Also look at WHO will be performing the work. Can you pick them? Do they have to be on an approved vendor list? One company had an approved vendor list, so their marketing material stated "pick any contractor you want". They failed to mention the contractor had to be on their list. When we looked at the list, we had never heard of any of them before.
As an aside, we bought a home warranty, their approved contractor (see above) stated there was nothing wrong with the upstairs A/C. It was not cooling. We had a contractor that we had used multiple times on our previous home come out and take a look. He wrote up a few problems. We sent the list to the home warranty folks, who promptly stated it was prexisting to the contract, so would not cover it.
Based on my (admittedly limited) experience, the whole home warranty business is not worth the money.