A:Answer Yes, you can. I do this all the time as I use them all day for work (so to get more total hours I only use one at a time in order to effectively double the use-time).
If you only pull one out of the case, your device (ex: laptop, phone, tablet) just connects to the earbud you pulled out.
All that the second one was doing was simply 'scanning' for the other one when it was pulled out, to see if the other one was already connected to something (at which point it just 'tags along'). But this is completely optional.
