(Apologies to the wonderful podcast "Always Take Notes").
When I worked in advertising the "contact report" was one of the top rules for client engagements. It was basically a record of the meeting — face to face or telephonically — and recorded the decisions made in the meeting. It was then sent to the client who had 24 working hours to make any changes to the note. If the client didn't have a comment then the contact report basically evolved into a contract.
This document was so important because if there was a dispute later, then it could be pulled out and consulted.
No-one was able to just make things up. The contact report kept everyone in line. And honest.
We recently sold a share in our business. A few months down the line we have a small dispute with our partner.
Luckily we have some emails indicating that what we were supposed to have said wasn't true.
However, I really do believe that we should have kept notes after every engagement. And not only ad hoc emails during the process.
The moden "contact report" can simply be an email after the meeting or engagement. But don't forget this discipline.
It will definitely get you out of trouble.
Just make sure you have a good filing system for your emails.