[All] Do you keep the charger plugged in?

Usually, when the battery runs out, I charge it.

I was wondering if it would be okay to plug in the charger before going to bed.

I saw somewhere that you shouldn't leave the charger plugged in for a long time,,,,

They say it's not good for your phone if you keep it on even after it's fully charged ㅠㅠ

I don't know if I should charge it before I go to bed...lol