When camping or away from the house I use it with water. The more the better - I'll keep a pan of water next to me and totally dunk it often if using while camping and this seems to work pretty darn well. If around the home I use it with oil. Mine is a Norton SiC stone. Occasional use with oil and using it with total immersion in water when practical seems to be keeping it like new. For light touchups I just use it dry. I have an older one that's AlumOx and a bit finer finish, but seemed to load up pretty fast unless used with oil.
Last couple of years I have transitioned to a natural silt stone that I use with water, no oil. It breaks down a bit just with water, with oil it makes a thick, unwelcome sludge. Is approx a 600 grit ANSI finish. I drilled a shallow depression in the underside and it doubles as a socket for a bow drill - is one of my most prized bit of camping gear.
Martin