Any day of calling is a good day, SnowmanMo said it perfectly no coyotes is a "Scouting Day". Even if I don't call in a coyote I usually learn a lot that day. Better ways to approach a stand, maybe a better stand location, look a new area, try different sounds.
Brian and I have hunted together a couple times we have totally different hunting styles, it has been a learning experience for me, I'm really looking forward to days when we can share a vehicle and really pick apart our stands, stand selections and calling styles. Already I've picked up one coyote in a place I wouldn't have called after hunting with Brian.