It really depends on the bag, but overall I would say that I definitely do not
obsess. Yes, I am certainly more careful with certain bags than with my $10 Old Navy canvas beach tote, hehe, but I don't spray them with anything when they're new, I don't sit them on fluffy towels in the car

, I don't punch strangers on the street if they brush up against the bag, etc. (that last one was supposed to be funny).
I do try to avoid taking any of my good bags out in the rain, and for the most part I keep them stuffed and in their dustbags and/or dustbag & box combination if they have a box.
I NEVER put any bag of mine on the ground, or the floor in a public place though! Because, really, that's just nasty to me. (I do occasionally set one on the floor in my house for a second, but not for long since I have a dog who likes to chew)