I hike and trail run with two dogs regularly. Sometimes I take them into 2nd to mild 3rd class scrambling situations, but am wary of several potential issues when considering taking them along, as well as when considering turning back without summitting:
1. Are their bodies and paws currently tough/in good shape, but not overused/injured from recent adventures? Will dog booties help and did I bring them along?
2. Is it cool enough out for them (their tolerance for heat and ability to cool off is less than mine)? Is the ground too hot for their paws or for their bodies to be constantly near? Is there water, snow, and/or shade for relief from sun and heat? Did I pack a way to provide water to them if necessary? They dissipate heat through paws, mouth, and nose; they don't sweat.
3. Are the conditions and terrain simply too dangerous,technical and/or rough to continue?
4. Can I carry the dogs out myself from wherever I am if necessary?
5. Am I prepared to stay put for several days for paws to heal?
One time, I did take the dogs into rougher and warmer terrain than they were currently prepared for and farmer's carried them out by their harnesses. 100 pounds on one side and 40 pounds on the other for a few miles with a few thousand feet of gain was the only lesson I needed to be more careful. They love hiking with me and will follow until they are hurting significantly, so it is my responsibility to be prepared and watch out for them.
Although agile, my dogs are more cautious than I am when it comes to climbing (and I don't spend much time beyond class 2 myself), so they are not likely to put themselves in a situation they can't get out of and even less likely to end up in a situation I can't get them out of myself without help from anyone else. It is nice to know someone might rescue me and/or my dogs if something goes severely wrong, but I don't go in expecting help will be available and would have to be absolutely unable to get myself and my dogs out before seeking assistance.
Below is a setup that I find helpful for keeping dogs attached to me and leashed in the backcountry. The dogs can pull me uphill. It helps me pull and carry the dogs ocassionally while scrambling as well. If I come across other trail users, I make sure my dogs are reeled in and out of the way.http://howlingdogalaska.com/index.php?main_page=product_info&cPath=28&products_id=117