>>1921945>answer the simple questionIf you want a simple answer, then yes 25L will do you fine for a couple nights.
But really it's a bit more complicated than that.
Where are you going? Mountains? Desert? Forest? Tundra? Car camping?
What season/weather? What's the temp like? Humidity? Snow/Ice?
How big is your tent, sleeping bag, mat? Do you have an ultralight cuben fibre 1p, a hammock+tarp, or an 8p waxed canvas hottent? Down sleeping bag or synthetic? -40c or +15c? CCF pad? Inflatable?
What kind of cooking setup and food are you bringing? Cookless? Alcohol stove? Liquid fuel? Dual burner propane?
Do you have to pack in your water? Take out your waste? Hang your food?
Are you bringing a tarp? Fire kit? Axe? Saw? Fishing supplies?
How comfortable do you want to be? Are you going to rough it completely or bring some comforts? In the end, it pretty much all comes down to that.
Want my suggestion? Get a 40-50L and that will do you for most 3 season outings for 3-7 days. Many great options sub-$200.
Want to go out in the winter? Get 75-85L.
No one can tell you what to get if even you don't know what kind of trips you're gonna do.
Get the cheap 55L Amazon Basics internal frame bag, go on a 3 day trip and see what you like and what you don't like. Refine your packing, cut out what you don't need, refine your sleep setup, replace shit gear slowly, make a spreadsheet and update it before+after every trip. Repeat this a bunch of times and then you wont have to ask stupid questions that no one can answer for you.
