Xp after level 30

The max level wild pokemon you can catch is level 30.

The answer is no. No advantage for leveling up over 30, other than power up your Pokemon to higher level. I don't care about experience since level 29 (currently half way to 35)

The level that a player will encounter a wild pokemon varies based on that player's level. Any two trainers at the same level will find a particular pokemon at the same level. And any two trainers at different levels thirty or higher will also find a particular pokemon at the same level. Reaching higher than level 30 doesn't change the levels that you encounter wild pokemon.

I'm lvl 39, & I care greatly about gaining XP in the long march to lvl 40. I'm not aware that I'm catching higher CP mons than a lvl 30 though. I think too, and it's only my opinion, is that not caring about XP after lvl 30 is a reaction to the vast emptiness ahead without apparent reward because the XP required at each level. For example, it's something like getting into lvl 37 before you're halfway through the game. What to do? Defer expectation perhaps as a coping mechanism.

I personally don't care about XP put this guy do!

i think it all goes back to what kind of environment you have , if you are in an area where poke stops and spawns is plenty one or two hours can give you the same xp a similar player do in a week or two , so i think it is not optional to not care sometime it is mandatory