I consider myself a simple man when it comes to many things; for example, I have one type of whiskey that I enjoy and buy every month. Sometimes I'll branch out, but I don't like to complicate things. Same with other stuff, like the clothes I wear, places I frequent, etc. I don't like too much variety as I feel it complicates things (there are exceptions, of course).
For many years I was that way with tobacco, and only wanted ONE blend that was my all day, every day smoke. I wanted to keep it simple. But I've since discovered that there are so many great blends out there that all suit different moods/seasons/etc., that it would be mistake to relegate myself to only smoking one blend for all eternity. So pipe tobacco is the one area in my life where I really like to branch out, try new things, read descriptions and try to pick out the flavor profiles... things like that. It's part of the experience for me now!
That being said, how I rotate really just depends on my mood. I smoke about every other day. When I'm ready to load up a bowl, I look at my collection and read the labels to see what I'm feeling. Maybe an aromatic, maybe an English, maybe a straight Virginia or burley, maybe even the old standby I mentioned above. It just depends on the moment and sometimes I smoke the same thing multiple times in a row. I just like to follow my heart (or maybe my nose, rather) and sniff out one that sounds good. I don't think about it much beyond that.
As for the pipes, I've got six total and I rotate through those regularly. My system is to set my lighter and tamper in front of the pipe that's up next in the rotation so I don't lose my place.