I would charge a lot to bag the back yard and cut it at a height so your blades don't hit the dog poop. and secondly unless the customer mentions anything about hauling the bagged grass away, it goes in there woods....if they want it hauled away its an extra 10-20 on top of the extra 20-40 for bagging the lawn depending on how many times I have to stop and empty the bags as well. I learned my lesson with that one. It's an absolute must to charge extra for removing the clippings from the property even if you can dispose of them for free, it still takes extra time to dump the bags into your truck or trailer, and time to unload them. and without a dump insert, or dump truck or trailer it absolutely sucks unloading 2000lbs of grass clipping/leaf mixture, and it has to be done the same day otherwise its even worse. that's how I deal with it. I don't clean up dog poop, I do try not step in it, and I pretty good at avoiding it with my feet and the trimmer, but I run it over with the tires on the mower all the time, that doesn't matter too me. maybe its just me. but when I bag lawns, which i only do after october 1st, and then leave it on for spring clean ups. I use more gas in the mower, and it more wear and tear on the whole machine, plus the bagger unit itself wears out eventually. So you really need to charge for all of that, and for me personally an extra 15 dollars a bag isn't enough especially if you have to stop mowing twice to empty the bags. I would say an extra 30-40 seems adequate.
fully lic. and ins. 10yrs exp.