Every pack I've bought bigger than 30 litres has quietly filled itself with things I didn't need. The smaller one forces better decisions before I leave the house, rather than relying on willpower once there's still room to spare.
It's a pattern I didn't notice until I actually compared trip photos side by side — the 40 litre pack and the 25 litre pack, packed for broadly similar day trips, weighed almost the same, because the extra room always somehow got filled with something "just in case" that never once got used.
Switching down forced an actual audit of what was in there: a second layer that had never been worn, a first aid kit duplicated across two pockets, and enough spare charging cables for devices I hadn't brought. None of it was wrong to carry in principle — it just wasn't being carried for a reason, only because there was space for it.
The smaller pack does mean occasionally leaving something behind that would have been useful, and I've felt that a handful of times over a full season of use. But weighed against every previous trip where the bigger pack came home with unopened pockets, it's a trade I'd make again without hesitation.