My opinion: If the plan from the time the year began was to start a business by the last quarter and every mechanism are in place to do it then start. If it wasn't the plan and the average income earner wants to do it because they just thought about then don't. Starting a business is easy anyone can do it but sustaining it is hard. Even if the average income earner is a billionaire without a plan the business would be more of a non-profit than a for-profit.