If you're accident prone, Apple Care + is probably a good move. That said, I've had every iPhone since the 3G and never once had a need for Apple Care +. I did get one phone replaced a few weeks after I received it under the 1 year warrantee.
Extened warrantee programs are money makers for whoever offer them. Like insurance, the pool has enough money in to to pay for all the warranted problems plus a surplus for the company selling these "insurance" programs. While I'm not sure of the total number of iphones I had (which is 10) because my wife started getting them with I think the 4S. She only upgraded every other year so we probably had about 15 now without missing Apple Care.
Don't remember how much extened Apple Care was over this period, but I'm guessing maybe $150. That comes to around $2,250 that I didn't pay over my IP career. So, even if I took my new X and tossed it in the ocean, I could still replace it and be ahead around $1,250.
But if you're accident prone, better get Apple Care Plus, especially if you keep the phone for 2 years.