If you live to age 90 and finish college but no further schooling, you've spent less than one-fourth of your life learning new material. And let's be honest, the middle- and high-school years were likely not the most productive for many of us. I was a relatively nerdy kid who took extra classes, and I still could have completed four years of high school courses in a lot less time. Of course, the social development that takes place during that time is important, too.

But here we are in the Information Age. Don't you want to take advantage of it? It's easier to get information than ever. And this learning doesn't have to cost a mint either. Check out this list of 37 places to take courses, many of which are low- or even no-cost.

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And while there are some definite advantages to acquiring new info when you're younger and your brain is super-flexible, being older has real advantages when it comes to learning unfamiliar stuff. For one thing, older brains are much better at self-directed learning, which means that if there's a constellation of subjects you're interested in, it's easier to set up your own "coursework" of sorts — from putting together a reading list, to creating a "final exam" that could simply be an essay based on your reading. Being better at self-direction also means you don't need the reward of a new baseball glove or the threat of punishment to get your work done, as you might have needed when you were a kid.

Data and statistics on senior learning. Useful stats that will inspire you to take a class. (Photo: Courtesy Babbel Magazine)

Other studies have shown that even though you aren't exactly a youngster, you can still grow brain matter by learning new things, especially language. (This has the added advantage of also slowing dementia; if you're already bilingual, you're more protected from it.) So now that you know you're absolutely capable of learning new things and you're motivated to do so, the final component is doing it.

Some rules for learning — at any age

1. Focus matters. No matter how good you think you are at multitasking, you aren't. Enough studies have shown that it you're doing more than one thing at a time, especially when it comes to learning, your speed and retention drops off. It's better to spend 20 uninterrupted minutes a day on the topic you've decided to master than an hour of distracted learning. You'll also find you are calmer and happier when you focus on one thing at a time — and if you're learning as an adult, what's the point of suffering through it?

2. Practice makes perfect. If you're picking up a new language, learning or relearning to play an instrument, or starting to paint, you probably already realize that you're going to have to put in the time. There is just no way around it; those who are best at a given subject are those who have practiced the most. (You may have heard of the 10,000 hours theory from Malcolm Gladwell's book, "Outliers" — that it takes that much time to become expert at anything.)

3. Learning should be hard. If it's difficult to do something (even maddening at times), you're more likely to really absorb it. As the authors of "Make It Stick" wrote in the Boston Globe: "When learning is harder, it’s stronger and lasts longer. Learning that’s easy is like writing in sand, here today and gone tomorrow." When you're stuck on a difficult passage that doesn't seem to make sense, or when you keep making mistakes solving a problem, don't get discouraged — this is when the most valuable learning is happening.

4. Your preferred learning style shouldn't be your go-to. Most people think that learning in their preferred way is better. (I like to read things, auditory learners like to hear information aloud, while visual learners like images, graphs and live-action descriptions.) But just because it's easier to learn in a certain style doesn't mean it's really better. "...you learn better when you 'go wide,' drawing on all of your aptitudes and resourcefulness, than when you limit instruction or experience to the style you find most amenable," write the authors of "Make It Stick."

5. Don't be afraid of what business guru Seth Godin calls "The Dip." This is basically a plateau that occurs in any business, learning endeavor or project. When you don't feel like you're getting anywhere, you are in this phase. It's often demoralizing, depressing or frustrating. Many people give up at this stage. You must keep going to achieve what you set out to do. Every successful person has gone through this part of the process, sometimes multiple times. Keep going. It's worth noting that this isn't a new idea: My grandmother called it perseverance, and she often called it "The Most Important Thing" — and of course she was right.

So go forth, and learn something new! You have every reason to.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.