I’ve learned that on the 12.9 iPad Pro (2018) you can stick the Apple Pencil inverted, with tip near the right edge. The magnetic adhesion is strong enough to hold the Pencil there, without the needless constant charging.
Aye! There’s two magnets on the iPad Pro 11". The iPad can hold the Pencil with either, leaving the stylus hanging off. It isn’t very secure but I like it when reading and highlighting, as it’s easier to get to. It also allows you more options when gripping the iPad—yay ergonomics!
I agree that it is no issue to have the pencil attached constantly, but I have noticed in November that my iPad lost about 10% charge over night when the Pencil was attached. That was something new to me. When the Pencil was not attached, my iPad only lost about 3% charge over night. I did some googling back then and stumpled upon this discussion:
Apparently, the depletion is not happening anymore with having the latest iOS updates installed according to a post from June in the mentioned topic.
Long story short: I do not think that it is a problem to have the pencil attached constantly but I prefer it to be attached only when I need it (attaching it for a few minutes is enough to work with it). Apart from that, it sits in my iPad case from “Almwild” - safe and sound.