I'm going to recline my seat on a 10 hour flight
Can you explain to me why you want to recline your seat?
It's very uncomfortable to sleep if the chair is upright.
It's understandable that you wanna be comfortable on such a long flight. Otherwise you could really make yourself sore.
Glad you agree.
I see nothing wrong with reclining your seat, as long as you don't go too far back and annoy the person behind you.