If I'm home, I'm using a computer or tablet, so I don't even turn Wi-Fi on my phone there.
People don't seem to think this stuff through. Although to be fair, most people have no idea they're wasting power, and Apple defaults everything to ON and makes it a PITA to turn this shit off. They even put fake "on/off" controls in "Control Center" that only toggle BT and Wi-Fi TEMPORARILY. Offensive disregard for the user's choices.
I suggest telling Apple to permanently respect the user's on/off choices no matter where they make them: https://www.apple.com/feedback/iphone/