On a light day, I will normally carry 3-4. My average is probably 6, and I have brought as many as 9-10 in a single trip. I don't always shoto everything I bring, and I normally go with my fiance, so it depends on what we want to shoot.
As for cleaning, I try to clean everything I shoot within a day or two, depends on when I have time. I give them a good cleaning after each trip- field strip, hoppes and patch, plus a bore snake just for good measure. Periodically, I will also pick one that has seen a lot of action or has been recently acquired and give it a more thorough cleaning- really get all the dirt and grime out.
I also tend to keep one of my carry guns set aside for self defense if needed. I try to always carry a clean gun for personal protection. At the very least, I try to keep a magazine full of SD ammo set aside in my range bag just in case, and it goes in my carry gun on my way out of the range.