It's hard to say, they're all different. I would think the smaller the dog, the less control he/she would have. If you think she is peeing too much, make sure to have her checked for a UTI. If she drinks alot of water, she will obviously go more.
I've been having a problem with separation anxiety, but Jake has been much better the last week or so. I was home with him for the first 6 months I had him because I was ill, so he has had a hard time getting used to me working. Fortunately, my hubby gets home about an hour or less after I go to work so that helps. Jake was getting very sad and wouldn't eat while I was at work. I took some advice I got here and it's working. When I leave, I don't make a big deal out of it. I started taking my keys and purse and leaving for very short times. I starting with going outside and waiting a couple minutes, then I'd come back. I'm gradually increasing the time, and he is realizing that when I leave, I will always come back. Now he's getting so much better about it, and he is back to eating his evening meal.