I used charge every night, but with this 8 plus I can go two days sometimes, like right now I’m on day two and at 66% yesterday wasn’t a heavy phone day granted.
I have no problem letting it go right down to the ten percent message and then some, I’m never far from a charging source .
My phone is on the charger the majority of the day. When I'm in the car, it's always plugged in and charging if we wanna listen to specific music. For trips (airport etc.), I generally carry a charger with me but keep my phone powered off unless I need it (If I'm traveling alone it stays on.). Typically my phone doesn't drop below 60%.
So far I charge it every night and do a top off during the day at my desk. I am not sure if its a good idea or not. I have been trying to figure out best practices on these devices.