My hiking partner isn't as old as me, but we are both pretty old school when it comes to packing our packs. Extra clothes, extra food, extra water or purifier, first aid, fire starter, rain gear, map, compass, head lamp, emergency bivy, etc. We look at some of the tiny packs others are carrying and shake our heads. In RMNP we even see quite a few tourists with no pack at all. They have a plastic grocery bag in their hand, or even just a water bottle, heading up to timberline or above. We also see a lot of people still heading up while storm clouds are obviously brewing. I'm amazed that more people don't die or need to be rescued.
What prompted this post is a review of a 22 liter pack that someone bought for winter hiking. Hey, no offense if that's you, but I couldn't use a 22 liter pack for summer hiking. In fact, my current summer daypack is over 30 liters and I wouldn't look at a pack less than 28 liters for summer hiking in the Rockies. And I pack lighter than my partner. I think he over does it, and maybe I do too, but there is packing light and there is being careless. I guess everyone has to figure out where they are going to draw the line, but yikes!
Where do you draw the line? I pack for the worst case scenario: I get hurt or lost and have to stay out overnight, possibly above timberline. It could happen to anyone. It could happen to you. I read about it all the time. I've been there when teams were out searching for someone that didn't return home. Mother nature isn't forgiving of the ill prepared.