@
[FONT=Helvetica]Tygerstrike [/FONT]
Insurance is only useful for things that you can't pay for. It's all based on luck, so think of it that way.
If you pay for insurance on your phone, let's say $100/yr(I don't know the actual rates) for an $800 dollar phone. If your willing to pay the insurance, then that means that you are expecting to lose or break a phone once every 8 years. If you are actually really careful with your phone, there is not much of a reason to pay insurance.
There is always a chance that something bad happens, but it's more likely that nothing bad happens if your truly take good care of your phone. This applies to your car, health, and house. It's unlikely that anything bad happens if you take the right precautions, but there is a difference between phone insurance and the other insurances I've mentioned. If you lose a phone, it's not a life changing event. Most people will have the cash to buy a new one. If you lose a 500k house to fire... most people would have serious financial troubles if they didn't have insurance.
If the loss of something does not threaten your livelihood, then there isn't much of a reason to insure it. After all, insurance companies do make money off of insurance. This means that it would be more likely that you make money off not having insurance than lose money. The necessity of insurance is based on what would happen in the worst case scenario.
I have personally had 2 phones over the course of 10 years; both of them still work today. I don't think it's too optimistic to think that you can keep electronics safe if you take good care of them.