Answer a few questions about your trip: how many nights, what kind of trip, the weather, your bag, who is coming. Packing List turns them into a list you can actually pack from. Quantities follow the trip: a pair of socks per night, fewer if there is a washing machine where you are staying, fewer again if everything has to fit in a carry-on.
Every suggestion is yours to change. Delete what you don't need and it stays deleted, even after you change the trip. Add your own items and they survive too.
The list is built on your device. There is no account and no sign-in, and your trip answers stay on the phone. The one thing that leaves it is an anonymous purchase receipt, which validates the subscription and restores it on your other devices.
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