Merging records

How do you know that you have merged all the records that need to be?

I keep track of new ward members that have made donations before their records arrive. I do the same for new converts. For the most part there are very few. You can scan the Add/Update Donors list for Nonmembers as well as Out-of-unit members without MRNs with names the same as, or similar to, Members on the list.