Are you from the US? If so that makes it a little easier since you wont have to deal with getting a dog into the country (which can be difficult). I have a dog, and some of my friends had them as well (note many were married or living with a significant other). Its doable, depending on the dog of course. If your pup has issues it can get difficult. One of my friend's dogs had behavior issues and was banned from a few daycare/boarding facilities, and no one would ever volunteer to watch it.
I know some people brought their dog with them on their internships. Boarding can get expensive if you do it a lot, figure 35-45 a day depending on location. Our dog was boarded for a few weeks at a time, places are fine with that but it buts a dent in the wallet if you do it a lot. Its a lot easier to find some place to board your dog than it is to find someone to dog sit at school...everyone is busy and its a burden.
I couldn't imagine leaving my dog but you have to think about whats in the best interests of your dog. I often ran home in the middle of the day to take my dog on a walk (advantage of schools where you can live within a mile of campus). Being married also helped, my wife often dealt with the dog if I had recruiting events at night. There are days you will be on campus with things from 8am until 10pm or later. They are rare but sometimes you dont even know ahead of time you are going to be stuck that long.
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Kellogg Class of 2010...still active and willing to help. However, I do not do profile reviews, don't offer predictions on chances and am far to busy to review essays, so save the energy of writing me a PM seeking help for these. If I don't respond to a PM that is not one of the previously mentioned trash can destined messages, please don't take it personally I get so many messages I have a hard to responding to most. The more interesting, compelling, or humorous you message the more likely I am to respond.