Our policy is pay all upfront if it's under a certain amount (otherwise it's half due, half pay later), yet people want to play games and not pay until the last minute. Annoying!
I am a hobby baker and make very few cakes for clients (deliberately). I get payment, all of it, prior to making and decorating the cake. The only exception is for someone I know very well and that I know pays on time. I think a lot of people have expectations and believe they are entitled to a lot more than their budget allows.
I've been doing cake about 40 yrs and nothing goes out my door unless it's paid for in full, no matter what size it is. Only if it's a gift from me to them.
Before I had a contract in place, I had one too many of those customers. I also had a couple that were short 40-50 and still expected their order. One lady was short 45, and I said "Oh, that's fine, but unfortunately I have to keep 1 dozen cupcakes." The look on her face was priceless. You get what you're PAYING for. Since then, payment in full before order is due or there is no order. It sucks that people do that to you, but you have to be firm. Non fulfillment of payment, no order. The deposit remains mine as well.