Relationships are first measured in how many dates you go on; then months; then eventually years. But in between the flipping of calendar pages and various anniversaries, there are a few major relationship milestones to consider. If you’re part of a couple, then we’re sure you have some relationship milestones of your own, but we wanted to look at four of the most tried and true.Meeting the parentsMeeting each other’s parents is a big deal. It means that things are getting serious and you see enough of a future together to get your families involved. In a sense, introducing your partner to your parents is similar to finally saying, “OK, we’re officially a couple.” Of course you were a couple before your parents had a chance to submit your guy to a barrage of questions about his job, goals and financial security, but it just feels that much more real once your mom makes him dry the dinner dishes. Meeting each other’s families also means you see the relationship as something with potential, and even if you don’t need or want your parents' approval, there is comfort in knowing that your partner gets along with your family. Taking a trip togetherThis is probably the second most important relationship milestone for couples. Taking a trip together is a test. Vacations are fun and taking a romantic trip together is a great way to boost your bond and spend a week moving from the bed to the beach and back again, but any type of travel can be stressful. Whether you’re going to Vegas, Paris or somewhere in the Caribbean, deciding to take a trip as a couple tests your ability to work as a team – from the planning (when, where) to the arrival (lost luggage and delays make even the happiest people crazy) to the trip itself (what to do, what to see and where to eat). Everything involves making team decisions and solving problems together. If you can do that, you can probably handle anything. Moving in togetherIf you survive traveling as a twosome unscathed, then moving in together is a likely next step (maybe not right away, but eventually). This means you’re ready to take on responsibility together (paying rent, dealing with chores) and believe you are solid enough in your relationship that you can share space. Sharing space isn’t always easy, which is why we see it as a milestone. If you can cohabitate without driving each other crazy or fighting constantly about housework or finances, there is a good chance you’ve made the right decision and the relationship is on solid ground. Getting a petSharing space is one thing but sharing an animal is entirely another. It means even more responsibility for both of you and more importantly, that you’re moving towards settling down. You may not have a house or any children, but pets do symbolize a certain amount of domesticity. Pets mean you see this as a long-term relationship and one that will likely lead to marriage, home ownership and maybe even kids, making it a pretty significant relationship milestone for a couple.