For me, it's not even so much about "getting through the day". I am always able to quick charge either at work, home or car. And, if I'm out and about I have a 20,000mah power pack.
However, I really resonate to your comment about battery health. I'm a very heavy user, so after six to nine months there is a noticeable decline in battery stamina. After a year it gets to the point where there is an appreciable decline. With my Nexus 6p, I really could keep it given the ever fresh software. However,I see myself swapping the phone this fall since it'll be a year with the battery decline that comes along with age.
At least 90 percent of folks I see use a case, which makes the whole argument about "how great the phone looks naked" mute. Glad LG is still in the removeable battery space. Just wish Nexus was as well.