Great question and very timely for me.
Like you, I've been an avid day hiker for years but I did my very first backpacking trip just a few weeks ago. So it's really easy to remember what I wish I had brought, and what I am glad I did bring, what I could have left at home.
What I wish I had brought - not a lot to add because I am an over-thinker and had my gear dialed in well before I left. But there are a couple items here:
- A chair. It was a primitive campsite but the preserve did have a picnic table at each site, so I didn't bring a chair, knowing I could sit at the table. But after an 8 mile trek with a few thousand feet of elevation change to get to the campsite, I really wish I could sit in a chair and lean back. Sitting up at the table was good, but my back didn't get to rest until I laid down on the bench seat. Sitting in a chair would have been great.
- Dessert. Yeah, I was really happy with my dinner and I did bring along a flask with whiskey and cigar for after-dinner, but I certainly could have enjoyed something sweet after dinner.
- More entertainment. After having read a few trip reports where people said it took anywhere from 4½ to 5 hours to get to the campsite, I decided to be on trail no later than 11 AM so I could get to camp, set up my tent, and eat dinner by 5 PM. I don't know what kind of shape those people were in but it only took me under 3 hours. Took me 5 minutes to find a spot and set my tent up, so by 2:10, I was at camp. I managed to amuse myself and enjoy my surroundings, but a deck of cards or a book would have been enjoyable, too. So I'll add something to that.
What I am glad I brought:
- Not gonna do a whole load out list here, but I was happy that I downloaded a playlist. The sounds of the forest were beautiful, but as I was laying in bed, some relaxing meditation music helped me fall asleep.
- Nalgene Ultralight Flask.
- Trekking poles. Not only to help with the hike but there was a guy in the campsite beside mine who had a brand new tent and had never set it up prior to going on the trail. I saw him struggling with his tent so I went over to ask if there was anything I could help with. Because he hadn't even taken it out of the bag before arriving at camp, he wasn't aware that he needed trekking poles BECAUSE HE BOUGHT A TREKKING POLE TENT! I was happy I brought mine as I could lend them to him to set his tent up for the night.
What I could have left at home:
- I bought the DJI OM4 gimbal for my smartphone with the idea of shooting some video. I was enjoying the trail so much that I forgot to shoot any video. Oops... LOL So that was a pound of electronics I didn't use/need.
“Between every two pine trees there is a door leading to a new way of life.” (John Muir)
one or more gifts or other benefits from the co-op.