How long does it take to forget someone?

For some it's in an instant and for others it may be a life time.
If they are around you or there are things that remind you of them, then you will remember them for a long time sometimes never forgetting them at all. However if their influence is removed slowly but surely you will forget them, and they will forget you.
Have you ever hoped that someone forgets you?
Life is like a book and when we meet someone they become a chapter, a character in our book and we in theirs. If you ever want to have someone forget you then just disappear, leave their book, in time there will be others who will overshadow your life's chapter in their book.
How can you make someone remember you?
There is no real way to have someone remember you, with age they will forget, however you can make them somewhat remember you by either causing them great joy or by harming them greatly, I guess in the end all it comes down to is how you want them to remember you as?