Lifelong learning, research shows, can make you smarter, richer, and happier. But, let's face it, making time to feed your brain is easier for some folks than others.

For entrepreneurs with growing businesses, parents of young kids, and others with jam-packed schedules, finding the five hours a week to devote to learning recommended by experts can seem impossible. If you're one of the extreme time crunched, should you just throw up your hands and accept your studying days are (at least temporarily) behind you?

Absolutely not, according to a helpful recent Medium post from Artem Zavyalov, co-founder of Highbrow. In it, he rounds up a host of tools that can help even the most over-scheduled squeeze in a little learning (including his own company's, of course).

Being less busy would be best (and science suggests old fashioned in-depth reading provides unique benefits), but if, for the moment, you're time for self development is limited, check out the apps and services Zavyalov recommends. Here's a sampling.