Back when wired IEMs or old school earbuds/earphones were given as freebies with the phones/other devices, some of us just lost them over time all the time, lol.

These days the $20 IEMs are really good and so just use those for outside use.

Right now the current marketed hype sets are the $20 Truthear HOLA, TANGZU Wan'er, 7Hz Salnotes Zero, et cetera.

There's a lot of earbuds cases these days that may be really easy to find, like put stickers/etc. on it to make it distinguishable. As in, always have a container for your IEMs so that they don't get damaged or lost easily. Treat IEMs/audio stuff as jewelry as when you drop them, the sound/everything can be damaged, and so yup, always use some caution when using them.

For $50 or so IEMs, parametric EQ, squig.link comparison graphs, et cetera, click here: https://www.reddit.com/r/HeadphoneAdvice/comments/1153zi3/any_advice_on_what_headphones_i_could_buy_for_my/j9iic7p/

Extra info on wired IEMs/headphones/Bluetooth/et cetera: https://www.reddit.com/r/headphones/comments/11a550d/how_can_i_learn_the_basics_about_soundheadphones/j9r9r48/