Guide
Every question in a handover, an audit or a sale is a historical one, and history is the thing nobody keeps.
Each of these has a definite answer. Almost none of them can be produced on request, because the record that would contain them was never kept.
A person leaves. The domain is on their account, the certificate renewal runs on a server they configured, the mail provider was set up with their login. None of it is written down because it never needed to be while they were there.
Someone is buying, insuring or auditing you. The request is not for the current state, which is easy, but for evidence over a period. Assurances do not satisfy it. Dated records do.
Something went wrong and the question is when. An incident, a dispute over what was advertised, a claim that mail was never received. The answer depends entirely on whether anything was recorded at the time.
Some of it can be pieced together from registrar emails, invoices and old backups, given a few days. Much of it cannot. Nobody can tell you what a DNS record contained before it was edited, or what a page said on a specific date, unless somebody kept a copy at the time.
This is the specific reason a record has to run continuously rather than being assembled when needed. By the time you need it, the window to create it has closed.
The wider version of this problem is covered in inherited infrastructure.
This is one symptom of a wider gap: nobody owns your domain.
Check yours
The free check produces the inventory. Keeping it dated from here is the part that takes time you cannot make up.