There are questions on here about getting married, having kids, and other major time commitments during graduate school. But one thing that I haven't seen posted -- but that I've seen come up with some frequency (at least in the US) -- is concerning people getting pets during their PhD. Yea, I know certain pets (e.g. fish and reptiles) take less time to care for than others (e.g. cats and dogs), but I'm specifically wondering about what to consider in the latter case.
Pro: Pursuing a PhD can be a very lonely process, so having some companionship can be worthwhile and perhaps even lead to increased focus and productivity.
Con: Cost and time commitment, particularly early on with a pet.
What are other things to consider in getting a pet during the PhD? Does the timing make a big difference? That is, should I wait until I'm ABD, or should I get one over a summer?
Does having a companion, like a dog, for example, often help students' productivity when they were otherwise adrift in isolation?
Also, I'd be interested to hear from a faculty perspective as to whether it's ill-advised to get a pet during the PhD. I assume most don't care as long as the student stays productive, but I'm curious if there are any anecdotes that support either the pro or con I listed above. Same goes for anyone who got a pet during grad school.
NOTE: The help center explicitly states that questions pertaining to "Life as a graduate student, postdoctoral researcher, university professor..." are on topic (emphasis added). Thus, this question appears to be fully within the stated guidelines.