Matthew 13:51 “Have you understood all these things?” Jesus asked. “Yes,” they replied.
How often do you check up on people to make sure they have understood what you have been trying to tell them?
I faced two types of history teacher in school, one who would give us a lot of information, only once, and one who would repeat stuff. I never remember what the first one said...
If we say something and never really follow it up, people will quickly forget what we have said. But if you are willing to follow it up and allow them to grasp the whole story, then they will remember things more.