A question I'll often get from my clients as they're making the transition from one AMS to another is "How much historical data do we need to convert?"

My preferred answer is always "None." The easiest data conversions are those with the least amount of data.

But the more accurate answer is another question: "What will you actually DO with that historical data, if it's converted to your new system?" In my experience, the overwhelming majority of data is never used beyond its original transaction. That suggests that most historical data probably doesn't need to be converted.

Yes, there are some significant exceptions, e.g., certification data. But most historical data probably doesn't need to be converted. Just ask yourself: "If I have that data in the new system, how will I use it?" If you have to think about that before you answer, you probably don't need to convert that data.