Since I've been getting more and more large orders, I felt it was time to create a deposit policy. This sounds fair right? It's at the link below.
http://www.frostedchiccakes.com/contact-for-order-or-quote.html

I require the deposit (50% up to $100) just to reserve the date. Payment in full is required by 30 days prior for weddings, 1 week prior for other events. I only require a deposit on weddings and orders over $200.

I would also add something to put a time limit on the re-use of the deposit- perhaps another event booked with 30 days etc. That way you're not holding a non refundable deposit forever just in case!

It's been like 5 yrs since I was in business so I'm out of date on the amounts etc. however, 'hold the date' deposits usually are applied to the total of the cake.
A 30 'extention' on the deposit is a bit short in my opinion. I would say more like 90 days .

Sure - 30 days was just an example! 90 days would be perfect!

IMO your requirements should probably be stricter.

For orders less than $100 I require full payment up front.
For orders more than $100 I require a 50% non-refundable deposit in order to book the date. the remaining balance is due 30 days before the event. Less than 30 days the entire amount is due in full.

I only take a $100 deposit and it's non-refundable and non-transferable. This is what it says in my contract:

A non-refundable retainer of $100.00 is due upon acceptance of contract in order to ensure booking of the event. No verbal bookings are accepted...
The $100 retainer fee is non-refundable and non-transferable to a different date or client, even if the new date is not available, or the event is totally cancelled. In the event that the client decides to hire another baker and does not pay the balance due, the retainer is not refundable.