"Know thyself" is one of the oldest, wisest maxims in the book. It helps in every area of life, but it also helps in relationships—even if you haven't been by yourself in years.
In this arena specifically, longtime singles may have something to teach long-coupled folks. In getting to know yourself intimately as full-fledged adults, singletons may inadvertently set themselves up to have better long-term relationships later in life. They know who they are, where they are going, and how to care for themselves emotionally and physically.
Coupled partners can hone these skills, too. You can absolutely take solo trips, make friends you don't share with your significant other or set up individual goals for personal growth, so you return to your relationship more rejuvenated than before. It helps to keep resentment at bay, too, which can often build up over time if you adopt too many of your partner's lifestyles and desires. Even if you're happily coupled or married, you should still take a page from the single playbook. Here's what married and taken women can learn from the unattached.