You guys get along with so little. Here's what I never leave the house without, carried in a Fjällräven Greenland size S bag...:

– phone (up until recently I had a tiny Nokia dumbphone for voice calls because it sucks when someone calls on the smartphone during navigation while on motorcycle...)
– wallet with home and office keys attached
– a metal ring coupled to the bag strap for car / bike keys
– case for glasses if I need to take them off (rarely used though)
– tiny knife that masquerades as a bottle opener
– bag with USB charger, power bank, assortment of short USB cables for all occasions, Arch Linux boot stick
– a pen and a couple of permanent markers
– travel toothbrush
– lighter (I don't smoke but it makes me friends)
– some lucky charms: gemstones picked by my daughter tied into a 'sausage' with some stretch fabric
– T1D stuff: insulin pens in a gorgeous leather roll made by a friend - glucose meter with accessories - bag with pen needles - plastic jar with lid for used needles - pocket scale for weighing stuff to calculate carbs - glucose tablets and Skittles (great for microdosing carbs)

Not in shot: wrist watch.