If your insurance covers accidental damage then you're fine. A lot of policies don't cover that, though. They will inspect the phone extremely carefully for signs it's been damaged, as even a small drop can cause a hairline crack in the screen that may only stop working weeks later (happened to my iPhone but Apple was very good about replacing it anyway). With a case, even if you do drop it, there is less likely to be visible damage on the outside of the phone itself, and therefore it won't look like accidental damage and may be covered by a warranty - in which case there's no need for the insurance during the first year anyway. I've learned my lesson about keeping phones away from water, back pockets etc. - I just need to worry about dropping it!
Personally I find insurance with accidental damage cover very expensive (typical seems about 6 pounds per month, which is over 140 pounds over two years) - I'd rather take care of the phone and self-insure. But perhaps there are better deals around. How does your policy look, if I may ask?
