I just found out that I'm now down to holding something like 997 MB of free space from my over 4 gig total capacity on my Apple watch S2. What should I remove that won't impact the watch's operation? I don't have photos on there as I can't see them. However, I guess some of my music needs to be gone, huh? If I remove it, though, will it be removed from my iCloud music library? I don't want to do that but remove some from my watch. What section of the music app to go to to find out what's on the watch currently?
P.S. Should the watch ever be hooked to the computer using its usb cable, or is that just for charging with an external adapter--the one which came with an iPhone?