I have four pairs of shoes, and my partner has no fewer than 10. I have one pair of Supadance for parties and shows, one well-worn pair of VeryFines for floors I'm unsure of, one pair of suede split-soled dance sneakers for lessons and overall practice (because they're comfy as heck!), and one pair of generics for backup.
As far as taking care of the suede, I've found the wire "shop brushes" you can pick up from Wal-Mart or any hardware store work wonderfully well for keeping the soles clean and well-napped. I have the actual Supadance heavy wire brush that you can get most anywhere for $10, but I find it makes them too nappy, and sometimes too slippery. I also have a nylon brush for removing dirt and keeping the shoes clean.
Watch out for floor wax/waltz flakes. Many floors we dance on around here are used by the "country" dancers, and they have the little "cat boxes" in the corner with wax. On more than one occasion either one or both of us have hit spots that almost caused a fall. We actually watched another couple hit a patch that caused us problems and actually fall. Clean your shoes after dancing at one of these places!
When we first started, I made the mistake of wetting the sole of my shoe to "scrub the dirt out" and do what I thought would restore the sole. Big mistake! The suede sole stretched and buckled when it dried, and it took a lot of glue and work to get them back normal again.
At studio parties we always have to watch for people who drip drinks across the floor. Nothing worse than getting a sticky spot on the sole of your shoe.
If you can't tell, I'm very particular when it comes to my shoes!
J