I've had service providers become much less interested after the money was paid. Before payment, there was a conversation. Afterwards, getting the work and the replies became harder.
I understand why a provider wants payment security. You're committing time and resources, and you want to know you'll be paid. But from the customer's side, handing over the money doesn't mean the service has been delivered.
There is still work to do. The promises made before payment still matter, and so does the communication while the job is happening.
I've been frustrated by that more than once. It feels like the provider's reason to pay attention disappears at the point where I need them to start doing the thing I bought.
That is a useful experience to remember when you're running your own business. What changes for the customer after they pay? Do they know what will happen next? Are they still getting the attention they were getting while you were trying to win the work?
In software, the relationship continues after someone subscribes. I want us to care about what happens while they're using the product, rather than treat getting the card as the whole job.
For a service business, the same concern is immediate. You still have to carry out the work and make it clear that you're doing it.
If you take payment up front, make sure the customer can see the service progressing afterwards. They have done their part of the agreement. Now they're waiting for you to do yours.
