I've had cell phones since the mid '90's and never purchased insurance and never had phone covers until I got my first smartphone, an Omnia. I also put a screen protector on it to protect it from scratches. (just in case)
Anyway, I've dropped most every phone I've had but from no more the 3 feet, on to concrete driveways, or tile floors, or carpeting and have never had a phone cease to work. They did get scratches however. I've only dropped my Omnia1 once from about 2 feet. I was sitting in a chair and it slipped out of my hand onto a plastic pad that's put under desks so that the chair rolls smoother. The case separated when the phone hit the pad but the phone was fine.
My point is I've gambled with no insurance for all these years so now I'm so far ahead that even I demolished a phone and had to buy a new one I'm still dollars ahead. But the piece of mind that comes with purchasing insurace has some value, so I say if you prefer having insurance, by all means, buy it.