I'd say it all comes down to either the majority ingredient in the soup or the ingredient that requires the most time. For example, a butternut squash soup with onions, s&p, veggie or chicken stock would take 10 lbs pressure for 55 min in pint jars as that's the guide for the vegetable canned alone. Tomato soup would just be ~45 min in a water bath. All of the canning guides and books outline how long to can each vegetable standalone. Hope that helps.
As a general guideline, most canned foods last about a year; they can go a little longer if they're in a cold, dark place like the back corner of a basement.
Also, avoid anything starchy in your soup--it makes it hard for the heat to penetrate all the way through the food to preserve it, so if you want to thicken anything or add potatoes, just do it after you've canned it before you serve it. Happy canning!
For soups, try not to mash or puree the vegetables, and from what I read online the soilds should be no more then 50% of the jars volume- you need plenty of liquid for expansion and to make sure it gets heated properly thruout. Most recipes for soups I have say to pressure can at 11 pounds pressure for 55 minutes. I am fairly paranoid so when I do vegetable soup I add raw cubed veggies into the broth, seal the jars, then can at 15 pounds pressure for an hour. So far the soups taste great and I'm still alive! :)