I typed myself a checklist that I use for most trips. Then, between a combination of the type of trip, and baggage policy of the airline, I pack what makes sense. Sometimes it's a carry-on, sometimes it's a checked bag, sometimes it's a shared bag between the two of us.

Backpacking is out of the question for me. I don't need 2 suitcases, but I'm not bringing the bare minimum to brag and save a buck on luggage. It is annoying to need things you could have packed, only to spend time and (inflated) money to go find it.