I'm coming late to the party, but I want to lay out my basic advice for prospective grad students. Keep a couple of things in mind, though. First, there's a lot here that needs to be fleshed out. This is just the bare bones version. Second--and more importantly--I make no claims about this advice being worth anything more than what you paid for it. This is just my sense of what I wish I'd been told before I went to grad school.
Enough throat-clearing. Here it is.
1. If you'll ever want to choose where you live, do not go to grad school. If you're a philosopher and you want a career in academia, you have no reasonable expectation of being able to choose where you live until you're close to 40 years old. By the time you hit middle age, you might--might--have some very limited choice about where you want to live. So if you really want to live in the mountains or on a lake, do not go to grad school. If you really want to live in a big city, do not go to grad school. If being with family and old friends is really important to you, do not go to grad school.
2. If you have, or suspect you'll ever have, a significant other who can't pick up and move at the drop of a hat, do not go to the grad school. This one's really just a corollary of #1, but it's worth really hammering, because not seeing this one coming can cause life-tearing sadness.
If your SO's career or family or whatever means they can't move whenever and wherever your career demands, here's the likely best-case scenario. You'll negotiate many, many years of a long-distance relationship, sacrificing plans for houses, kids, and dogs. You'll never take vacations, because any time you have off from school and work, you'll only want to spend with your SO. When you finally get to live with your SO, you'll be able to only because you're making sacrifices in some aspect of your career. Maybe you'll leave behind a great a bunch of colleagues and a college that suports the kind of curriculum development you're into. Maybe you'll have to turn down an offer from a Leiterrific department. Maybe you'll have to turn down an offer that would have paid for the house you've always wanted. Whatever it is, you'll give something up to be with your SO. Remember, that's the likely best-case scenario.
Here's the worst case, but still appallingly common scenario. You'll one day have to choose between your career and your SO. Given what, by that time, you'll have invested in both philosophy and your relationship, that choice will likely be one of the most painful things you ever experience. If you can, better just to avoid ever having to make it.
Okay, this post is already too long, and I haven't even gotten around to my third piece of advice. Stay tuned for that.