Get over the idea that only children should spend their time in study. Be a student so long as you still have something to learn, and this will mean all your life. ~Henry L. Doherty
The internet provides a vast resource of material to help people learn different skills. Before returning to school locally, I refreshed my "educational skills" by taking a few classes at the University of the People, a tuition free online institute. Recently MIT announced online-only, graded courses for free. For a small fee students that pass the course can receive a certificate. Another option is ALISON - with free online classes in a wide variety of material. Out of Ireland, Alison has course work in business management to IT skills and provides certificates.
With the world at our fingertips, much of it for free, we have little excuse to let our minds become stagnant.
Some other free learning sites: