But I already learned that...

I was re-reading a technical book the other day and was starting to get annoyed at having to re-learn some things I had learned previously, but have since forgotten. Then I began to ponder the idea of why we forget. There are some people that have a photographic memory and never forget, but they are rare. Consider for a moment what life could be like if you never forgot anything. Suppose that every time you got into a car, you could remember the horror of the car accident you had ten years ago. Maybe you would be flooded with the pain of being lost every time you went to that same grocery store you were lost in when you were five. It may be so severe, you would need to find a different place to shop. So forgetting is not such a bad thing, but it can be inconvenient at times. So like Monk says "It's a gift.. and a curse".

Don't beat yourself up if you have to 'sharpen the saw' (a la Steven Covey) and re-learn things. Take the opportunity to re-think the information and hopefully gain from the experience.