Every delivery is accompanied by the criteria it was built from and the counts at each step, so the number can be checked rather than taken on trust.
Monitoring
Watching for the configuration changes that quietly stop mail arriving.
Change tracking
What moved since the last delivery, so a refresh does not read as a new universe.
Authentication
Sender records configured and verified against what the receiving side actually reports.
Bring the file you already have and we will tell you what is still usable.