Jeans are an extension of your very skin (can you think of another singular piece of clothing that is as close to your epidermis as often as your jeans?). We don't as much break them in as we do treat them, develop them, and even raise them. Every day you spend with your jeans, on or off, they become more yours--any breaking-in process should reflect just that.
Lest it sound like we're telling you to suck it up and just wear them, we do have a few suggestions to help get you on your way to changing a recently-bought pair of jeans into something you can one day truly call your own.
Most of our lives start at home with our parents. Your denim can start this way, too. Wear your jeans at home as you would your PJs. Even sleeping in them for a few nights can help loosen up tight fibers--if you're doing this with raw denim, tread carefully around your white sofa or favorite white sheets. Remember, indigo rubs off.
You may choose to give them a proper washing (which would stop the pesky indigo from rubbing off), but you can also just let them soak in some cold water for five minutes. This will remove most of the stiffening chemicals that are only there to make denim easier to handle in the creation process. You can also wear them in a cool bath for just as long and let them dry on your body as you go about your business at home. Another option is to leave them in your bathroom for a week. Steam from the shower will work on loosening them up as well--again, just be cautious of the indigo coming off or upsetting any roommates with your messy clutter.
But your jeans aren't homebodies. Most of their lives will be spent going out, which means that you should also consider introducing them to the travails of the outside world. We don't suggest wearing them to the gym (which would break them in but could also elicit funny stares), so start with doing a few squats in them at home, wearing them when you're doing some work around the house, or even on short bike rides. If you still have your Wii Fit or a stationary bike, you've also got the perfect place to start breaking in your jeans.
Of course, there are more novel ways to break in your denim, with varying states of distress involved. If you're near the ocean, try going for a dip and letting them air dry to get a lovely aged patina. Getting them wet and rolling around in the sand will help to fade and loosen them up at the same time. Wear them camping, bring them snowboarding, skiing, or just rock them next time you have a big night out on the town. They may be uncomfortable at first but there's a little bit of truth in the saying, "Suffer for fashion."
How you break in your denim is a personal choice and should always reflect you, the wearer. The main thing to keep in mind is that your jeans will be with you for a long time. If you want to prepare them, the best thing to do is just dive in.