It depends on one's line of work & nature/purposes for the trip - local vs. out-of-town/travel; and, whether one has access to satellite offices/field support vs. being self-reliant.

Client consulting & tech support in the field (and, that includes traveling with Mrs. L & others in semi/vacation mode) - I always carry spare/extra items for contingencies - but, pack & use the most appropriate bag or briefcase for a given trip. One of the key is to pack items in pouches or sleeves/bags to avoid a nuclear fallout, dropping & spreading things all over (and, mostly under the airplane seat in the dark (cabin.)

This is one of my visual packing checklist - some things are taken out while other items might be added. For simplicity, I much rather take a 2nd. set of noise-isolating/cancellation in-ear headset vs. over-the-ears. It all fit inside this STM 13" laptop (vertical) bag - also, small backpack or classic Coach leather briefcase (non-expandable)



With a bigger Timbuk2 backpack as carry-on, I can pack an additional medium packing cube easily with a change of clothing for 1 or 2 nights, and toilety/3-1-1 bags. Flexibility is the key to best packing practices.