How long does it take you to forgive someone that

Forgiving someone isn't for them, it is for me. When I forgive someone who has wronged me, it is I who sleeps better, doesn't keep gnawing at the injustice done to me. I forgive because as long as I don't that rot is getting rent free space in my head. How long it takes me to realize it depends, once I realize and know that it is bothering me way more than the other person, I let it go. Sometimes, it is days, sometimes it is weeks or months, or years.