Lol my wife used to ridicule me for this stuff. A new battery is chump change (even full price of $79) so why I am I like this? I can buy a new battery in only a few hours worth of work, but I still look into it like a fiend.
Yep yep - same here.
I believe in karma to an extent... I figure those of us who take care of our stuff like this - we'll be rewarded with better usage times/happier devices - it's almost a hobby. Sure batteries are cheap but I like to think my battery is happier with me than the average Joe.
My wife lets her phone drain to 0% all the time, she doesn't give a thought about her battery. She uses about 150+ more cycles than I do in a 2 year timeframe. Her design capacity is usually identical or close to mine at the end of those 2 years. So while your wife does have a point, I still like to think that my phone is happier and I'm just taking care of it because it's a hobby of mine. I've also learned a TON about batteries too.
After 1.7 years:
Our 6s+ --- My wife had 370? charge cycles and 94% design capacity.
My 6s+ ----- I had 230 cycles or so and 96% design capacity.