In addition to my meter case, Skittles, fruit leathers, and insulin pen, I have a tiny case in my purse (I think it's meant to store SD cards for cameras) that has some pen needles, alcohol swabs, batteries, and a quarter (to unscrew the battery cap).
When my pump starts showing 2 bars on the battery indicator I add a spare lithium battery to my little backup pouch, the battery usually lasts about 2.5 months in my Animas 2020.
Yes I carry batteries, the MM pump and meter use a AAA Energizer
I carry everything needed to service my pump for a week and it all fits in a small leather bag I take it everywhere. If I leave the house it goes in my truck or car and the only exceptions are the gym or cycling. More than one time I have had to cancel my plains and go home because of a pump issue...bolus for meal and get a no delivery, slide into a booth at a local bar and catch infusion site on the corner of table and rip it out.
Murphy's law...something will happen sooner or later.
Ofcourse Mike ...batteries !! I carry 2 in my meter pouch . I recall looking for my fav. AAA Energizer brand , while in the Netherlands 2 years ago , because I forgot to take spare ones from home : NO such luck ...got my exercise in visiting many stores and went for the available brand .
I learned the hard way to carry back-up batteries for my meter at all times. If I were using a pump or CGM I'd carry back-up batteries for these, too. Having my dependable equipment go belly up when I was thirty miles from home in the middle of my work day at the world's largest factory (a 25 minute walk from desk to car) taught me to be battery aware!