I also believe in the law of averages, but did not know that it had any time factors associated with it. I had a good day today so the chances are that next time will be a bad day to 'average' things out. If that is the case then why bet next time if you presume it will be a bad day. If I take 1 day off, will that be the bad day, or will it wait until the next time I choose to bet?

There is no mathematical reason to stop. Each new race is a new event, and nothing from the past will change that. Yes things will probably average out, but there is nothing to suggest it will happen straight away.

At the end of the day, as long as you are comfortable with what you are doing, then who am I to argue. Good luck and I hope it keeps working for you.