Unless you have a particularly gifted memory, most people would say their memory is lacking at best. But a lot of what modern day people are trying to remember is surprisingly abstract. A person's name is just a sound that we associate with them. You can't see or feel a date: it's a globally agreed upon framework to structure time that tries its best to fit in with the earth's orbit around the sun. Our brains struggle with abstract.
Spaced Repetition is the systematic increasing of time between recalling a piece of information. Starting regularly and eventually waiting weeks or even months as the information becomes solidified in long-term memory.
Before we get into the "how" of Spaced Repetition, let's talk about what problem it solves.
In the fast-paced world of learning, mastering new information can feel overwhelming. Whether you're tackling a new programming language, absorbing complex technical concepts, or even learning a new skill, our brains are constantly bombarded with data. To manage this flood of information, one of the most effective and natural strategies is chunking.
Your brain has two primary "modes" and most people don't realise just how important it is to use both of these modes together when learning something new.
I didn't go to university. It took me over a decade of professional life to discover something that I wanted to study. I'm now on my second career as a self-taught software developer.
I have proven to myself that I can make it as a developer without formal education. But I am left wanting more. It's not about money: I don't think six years of a part-time degree would produce a monetary increase that I couldn't achieve through professional experience and grit in the meantime.
During the summer of 2018, as is common in the military, I was assigned a new role that required rapid skill development to be done by last Friday. As is not so common in the military, that skill was coding; and I was instantly hooked 
Work wasn't "work" anymore: it was adventure; it was exploration; it was discovery. I fondly remember the penny-drop moment when I wrote some code that looped and printed a statement ten-thousand times in an instant! The potential was exhilarating.