I had to charge my PW about every 3 days when I still used it. Wifi off. I like to charge at 33 % or in that arena. Now I use my basic and I charge it a tiny bit less than the PW. 4 days maybe? Not sure.
But I read a few hours a day (4 ish?)and I have always had to charge my kindles about every 2-3 days. Same with the K3. K1 even more often.
Again, I don't like to go down to low on the battery. I always worry I run out when I lay in bed to read.