How far in advance do you need to book Mike?
Impossible to say. Since there is only one of me, availability is basically hit or miss. Someone might have just booked your event date while you were reading this or it could remain available right up to that day.
That means there is no simple definitive way to answer this question. Therefore, Mike's booking policy.
Mike's Booking Policy
It is "the first person to supply a deposit, books him" policy which is fair to everyone. Mike does not use the marketing gimmick of saying that you better book now because many people are looking at your date. Even when it is true, it still sounds like a tacky high pressure sales pitch. Mike is a straight-up easy-going guy, no gimmicks.
As soon as possible after you decide that you want to book him for your event, take a look at his up-to-date posted schedule. If available, use Check Availability box on that page for first contact. If you have already used that, then simply send an email or call him and state that you have the deposit ready and want to book him.