I haven't flown more than about 6 hours during that time. And most of my flying isn't redeye - so I'm not trying to get sleep at night.

But I know how much of an issue it is for me - and figure that even if the person behind me has plenty of space, they're likely to be more comfortable if I don't.

And it's not like I'm purposefully putting my knees up against the back of the seat to make it so that the people in front of me can't recline. That's just naturally how long my thighs are. When I'm sitting upright in most plane seats, my knees rest against the seat in front. If I don't know they're trying to recline and get out of the way, they aren't going anywhere. I usually actually try to slide my feel further under the seat and allow them to recline if I know they're trying. Unless they are dicks about it. Then I just sit normal.