I charge mine overnight as I've always done since I've had cell phones. Never had any real battery issues with any of them except for the occasional defective battery from the start. My wife and I both got a new S9+ about a month ago. Hers was great and mine was horrible for battery life. I could watch the % drop quickly doing nothing. I ended up returning it for a note 8, but the 9+ was really the better fit for me so I returned to the S9+ on Saturday. This one is much better than my first one. I'm getting solid battery life. I charge overnight and so far I'm at 35-50% at bedtime after a 16 hour day of use. I don't use wifi very often due to no good home internet options where I live. If I had wifi at home it would definitely help my battery life. I leave everything else turned on since I use it most of the time. Overall I've been satisfied with the battery. I know they say the batteries are happiest between 40-80%, but to be honest it's more stress than it's worth to worry about it. I just charge overnight and know I have enough battery to go all day. On the off chance it's a heavier use day I can do a fast charge top up and be good to go.