For the duration of the 6s Plus that I had, I only ever used the headphone jack maybe half a dozen times. And for the next half dozen or so times during the next year I have my 7 Plus, I'll just use the lightning headphones that came with it.
I forgot to bring my new headphones to the gym today. Generally leave normal earbuds in the center console for the gym or beach. Totally spaced out and didn't think to swap them out!