AW2725DF, question about HDR

Hi,

Im new to hdr and i read on reddit that it's not recommended to leave the HDR always on ( on windows i think)

And just pass the setting on for hdr content ( like game or média )

But this is my question , when im on youtube or watching anime and playing game should i turn it on even is the game or the content is not HDR ?

And why i can't let it on it's gonna reduce the lifetime of the monitor ? My display is a AW2725DF 

What HDR profile should i use ( currently i use the PEAK1000) ?

Thanks