I´d like to compare this work with the work of a doctor - you try your best
to treat and hopefully heal the patient, but in some cases its not for sure.

Nevertheless the doctor gets paid for his time and efforts on the patient -
no matter whether the patient recovers, still is sick or even dies.

I saw it too often, that without charging a reasonable downpayment prior
any test - customers let you go ahead in your work. They verbally accept
a rough price estimate - but when they get the firm price - even below the
accepted estimate - refuse to contract and / or pay.

I think I have heared all existing excuses - and that stopped immediately
after charging a downpayment. And a part or all - depending on the amount
- will be kept if no final order is given.

Why should the paying customers cover the time and expenses for unsuccessful
cases?

+++

In this case it would be "You Die - No Fee"