I have 2 dogs and am currently in a master's program. I'll be starting a PhD next year. Dogs are a lot of work, as you probably already know, but I cannot imagine my life without my boys. I live pretty close to campus, so the first year I just made sure I came home every 5-6 hours to let them out. This year I actually hired a dog walker, which is basically where all my money goes. Nonetheless, I actually think having a dog in grad school is easier than having a dog in the "real world." I am not in a lab based program, so I can easily work from home. My schedule is pretty flexible, aside from having to be on campus for class, so it makes it easy to spend time with my pups. It also forces me to exercise and get out of the house (especially on the weekends, when I could easily stay in and work all day). Anyway, in sum, I think you can make it work-it just requires some trade-offs and sacrifices.