Mind your budget
If you are handing your teenagers $600 smartphones, that's your poor judgement. If they just "have" to have the latest model or "they'll just die of embarrassment" maybe it's time they got a job or start thinking of how behind they would be with no phone at all.
Phones are a commodity item now. The factories that stamp out the iPhones and Galaxies are probably the same ones producing the off-brand stuff. I picked up a Blu Advance for $99 and it's given me good service for the last bunch of months. It also has dual sims that I use to have a personal and business line. Not going to get that with Samsung or Apple. I also have replaceable batteries (hello Apple!). At the end of the year I bet that I will be able to find another phone in the same price range with 2x the performance I have now and I can upgrade. I'll flog off the old phone if it's still alive and have an amortized capital outlay of $10-12/month instead of $60/month.
I started off unlocked and contract free with the Blu. I can swap between AT$T and T-mobile or one of several service resellers and keep my phone number to boot. Right now I'm with Net10 for $50 month, unlimited everything (for a certain value of unlimited).
I could get insurance, but it will likely be faster to just order up a replacement phone and pay for it myself rather than go through the hassle of dealing with the insurance provider. For me, time without the phone would be a bigger factor than spending the extra $10-$20 over what I would have paid into the insurance.