Not in the legal sense, but a handfasting would be just that. The term of the handfasting are entirely up to you, though ‘A year and a day’ is common. At the end of the term you can choose to renew it or not. Unless of course you have chosen ‘for life’ as your term. 
I fully, but respectfully, disagree.
I’m speaking from the start of my third marriage, the ending of the second one was pretty well discussed on these boards if you want to go searching…
Still, despite the disasasterous end to my second marriage, I felt the need to get married again. Perhaps it’s just social conditioning but I believe that people are, in general, better in pairs than alone. We have the pre-wired need to get with somebody and form permanent relationships. The history of our culture, media, art, and writings are filled with documented evidence of this drive.
Once you’ve found that somebody - from amongst the many somebodies out there, I think it’s important to declare that fact. Marriage is that declaration. Sure, there’s legal stuff wrapped up in it but that could all be handled with contracts if you wanted. Even the arguments that having kids needs marriage is empty in light of the current laws surrounding child custody and support.
But - that declaration - in front of everybody that’s important to you, in front of God, is important.
What an empty thing we’re making of marriage when we decide it’s all about health benefits, child custody, and shared property rights.
ETA: Matthew 19:5, “…For this cause shall a man leave his father and mother, and shall cleave to his wife; and the two shall become one flesh?”
…I like that word, cleave in this case - seems better than simply “join”. There’s a need expressed in it, a biological desperation, of sorts…
Guys get married so they never again have to worry about having sex regularly. These men are sadly mistaken.
This is true for me, as well. Marriage (and we didn’t bother with any ceremony) is not about how the couple relate to each other, it’s about how the rest of the world relates to the couple. It says “this is my nuclear family”. It says “I am putting this other person first”–in front of my parents, my old friends, everyone. It means that if you want me, you take him, and vice-versa. And it does it in a way that is inoffensive and non-confrontational. Humans are social animals: we live in communities that are complex webs of ever-shifting personal relationships, and we use signals, like marriage–and adoptions, and graduations–to signal when those relationships have shifted.
When I was living with my boyfriend, people treated that relationship differently than when I was married. And they should have, because I married him when I realized he wasn’t my boyfriend anymore–he was my family.
ETA: my need for insurance hurried the time table a bit. But the underlying issue was that of status: we were family.
Marriage will change a relationship. Better or worse, but it will change. I prefer shacking up. Both seem to try harder because the legal and binding aspect is gone. You are there because you want to be ,not because it will cost you a fortune to get out.
For my serious answer, it must be said that I’m Catholic, so I view marriage as a sacrament and a vocation. Not everyone is called to be married, but it is a great blessing for those who are.
I don’t know what guys you know, but that’s not what most of my married friends (both male and female) say. Maybe your married guy friends just picked the wrong women for them.
My wife, prior to our being married, insisted that marriage was sort of an empty gesture – that two people are either in love or they’re not. And I agree that marriage isn’t a necessary part of comittment.
There are indeed legal, religious, and familial/community attributes to marriage. To me – a healthy, heterosexual atheist who has never in my adult life lived in one place longer than 6 years, is not close to my family, will not have children, and has never had a problem finding a job – none were of any concern. Beyond the fact that I love my wife, there were only two (related) reasons I had for getting married: (1) formal ceremonies increase the weight / significance of an event (as any churchgoer knows), and (2) that significance is augmented by making the ceremony public.
For similar reasons, about 10% of the cost of our (relatively inexpensive) wedding was spent on our custom wedding rings, which were designed and forged by my cousin. Whether the impact is simply psychological or not, the symbolism exists and is important; I think of it as an outward display of our duprass.
My wife says that an added benefit is that it’s nice to just be able to hold up her left hand to blow off guys who hit on her. 
Pay no mind to me. I was just joking on an old marriage meme. I forgot to write my serious answer in the same post.
“Marriage and sex, I tell you, that’s all my wife and I ever argue about. I tell ya, she charges me too much!” ~Rodney Dangerfield
Eh, no biggie - a good (married) male friend of mine often jokes that the reason married people have sex more often than single people is that the opportunity is just there most of the time; he can just say to his wife, “hey, wanna?” and she knows exactly what he means, and into the bedroom they go. (Not so often since their daughter was born, but you know what I mean.)
Tell that to the more than 50 percent who get divorced. Then how many stay together in misery? Not much of a calling.
For me, the reasons to get married were the legal ones and the public declaration that my husband my family. I’m close to my immediate family and have a large extended one, so that change in status was important to me. For my immediate family, it meant that my husband was an “official” priority and a member of the family. For my extended family, it means that there’s no question about whether I have a significant other to invite to weddings, whether I’m between boyfriends, living alone, etc.
I like having made our relationship public. I like having a relationship with my husband that is recognized both legally and socially. We’d been together for so long that I really didn’t expect our relationship to change at all when we got married (and it didn’t internally) but there was definitely an external change. I don’t wish we’d done it sooner (we waited until we were ready), but I’m certainly glad we did it, and I don’t consider it meaningless.
Even when you’re just living together, it can be hard to break up. Somebody has to find a place they can afford to live and it’s not gonna be me (it’s my house.) At least I don’t have to give her half of everything! 
It’s my opinion and I stick to it. If you wish to discuss this further, there’s other places for it.
How about the issue of commitment? If you’re not willing to commit to your SO, why should the government or their insurers or employers or whoever commit to you?
Commitment comes in many flavors, and plenty of people don’t consider a legally valid marriage to be the gold standard of commitment. Thus many of the responses in this thread.
That’s not really what Quart is asking-obviously commitment comes in different flavours. But if you’re unwilling to meet the standard provided to you by society, why should you reap the benefits it provides? It’s an easy yardstick. If I were an employer, I would not want to help insure someone’s boyfriend of the week.
Why did I get married? I really don’t know, it wasn’t a good time in my life.
I do know that my now-spouse was the one who wanted to get married, but I was the one who saw marriage as a lot more than shacking-up-with-a-big-party.
There are all sorts of other happy mediums out there, though. For example, my previous employer offered domestic partner health benefits, and there was a very detailed definition of who qualified as a domestic partner for that purpose; it required, among other things, having lived together for at least six months, and not being married to (or in a domestic partnership with) anyone else. There are certainly marriages that break up more quickly than that.