When was the last time you cleaned your attic? Very commonly, your attic becomes a 'graveyard' for past items that you do not use. When you clean out your attic, you find things that you forgot about and meant to use. Also, you find things that you forgot about and that you can use today. You may find items, that you acquired in the past, that may prevent you from 'paying for' it, now.
Instead of experiencing the same lessons again and again, by searching your attic, you may find the things you learned from a past similar lesson. Have you ever 'came-across some useful information? You knew that it was useful, but you didn't need it at that time. Yet, you knew that you would need it, in the future, so you wanted to keep it. Unknowingly, you just threw it in the attic.
Also, in your attic, you have junk, things that just take up space; disappointments, let-downs, failures, etc. Every time you put junk into your attic, you have less space to put something useful. When your attic is full you can no longer store useful information. There are many people with full attics that never revisit their useful items and never throw-away junk. So, when did you clean your attic last; a year, 5 years, ever? Unlearn.