The number three will have a personal meaning to you that no one else can know about. You associate three with money. Many people regard three as a lucky number. The Celts liked the number three as it was easy to remember, they had to memorise everything before writing was widespread. The Celts recorded some of their ancient history as triads. If I was to list three things,the list is neither too long or too short. Perhaps, and this is only a guess, you consider three of something to be a comfortable number to have in relation to financial dealings.