There’s a more than 1,000-word story in today’s New York Times about giving someone you’re dating the keys to your apartment: Is it a big deal? Is it a sign that he or she is The One? Should you change the locks if you break up? I suppose that for me, giving someone a set of keys to my apartment would be a big deal, because I don’t really like having guys over unless I actually like them. My teeny apartment is my home — I don’t want to bring in any riffraff. Annika knew that her relationship wasn’t over when she and her man took a break and he told her to keep the keys to his place. And Amelia thinks the key thing is a big step in a relationship, but so is an offer to dog sit if she goes out of town, or picking up her favorite things at the grocery. What are the relationship milestones that tell you when things are really getting serious?