I had a very classy backpack for hiking. I didn't just go for an afternoon but for up to five days.
I live close the the Canadian Rockies so there were excellent opportunities for backpacking. I once went into Mt Assiniboine (11780 ft.)which was a five day trip into the wilderness. We didn't climb the mountain as it's a very technical climb and I have no experience with that.
In backpacking you must pack: food, cooking utensils, water treatment kit, clothing, sleeping bag, sleeping mat, tent and a few other goodies. Don't forget the rain jacket or the wind shell!
So your backpack could weigh up to 50 lbs. For this weight you need a good pack that would make it comfortable to carry.
I bought such a backpack that would hold 90 liters. My foresight wasn't that good as my backpacking days were ending. As a result I only used the backpack a half dozen times.
I've kept the pack just in case I would go out one more time. But I realized that when downsizing the backpack could be sold.
I advertised on Kijiji and never heard anything until a lady called two days ago. She came immediately and bought the pack as her son was going to Australia.
Now she told me that when they were looking at my ad the son said isn't that funny how he got is Grandpa to model the backpack! When the lady gets home she will tell her son it was Grandpa's pack and he actually used it.