Setting expectations before something goes wrong.
WHAT TO TELL THEM
How often backups run What is included, and what is not How long copies are kept How to request a restore Whether restoring costs anything How quickly it can be done What they would lose in a restore
WHAT CAUSES DISPUTES
A client assuming backups exist from any date they choose A client assuming email is included A client assuming a restore is instant and free A client assuming the host keeps everything indefinitely
All of these are reasonable assumptions if nobody said otherwise.
PUT IT IN WRITING
Two paragraphs in your terms. Specific about frequency, retention and what is covered.
IF YOU DO NOT PROVIDE BACKUPS
Say so plainly, and tell them what they should do instead.
Silence is taken as a promise.
WHAT TO DEMONSTRATE
Restore something for them once, so they understand what it involves and what is lost.
CHARGING FOR IT
Managed backups with a guaranteed restore is a service. Price it rather than absorbing it.