We've been bathing them once a week, mainly because they get into so much crap (not literally) in the back yard. We have a HUGE back yard, and there's a lot of stuff back there. Mostly, it's just dirt. They're still only about 4 months old, so they get into just about everything. Ten days until puppy kindergarten!
When we are not home, they only have access to one room - their room. It does smell a little like pee, but not terribly so. I think the pillows on their crates still retain some of the smell. When we are home, we close the door to the upstairs and most of the downstairs rooms. They will get into anything - I wish I had a nickel for everytime we've left the bathroom door open, only to see them BOTH prancing about with a floor mat in their mouths. Geez, they're just pups. Last night, after finding some cool (to a puppy, that is) stuff in my office, they both began scratching to get in - and we were both OUTSIDE the door! I kept saying, hey Einstein, we're over here!
The female also tends to have - accidents. And I mean, accidents - she pees sometimes when she naps. She'll be right alongside the lounge chair sleeping, and when we get up to take her for a pee run - she'll be wet already. So, she gets a bath.
But I definitely will take that into consideration. One thing I DID notice is that some odor killers do a great job. We have a wood-burning stove and when smoke gets in the room, doggie smell goes RIGHT AWAY. Nothing like charcoal dust to absorb odor.