This post is more a tip than anything else, so we'll make this a citations "lite" post.
Recently, I've posted Civil War pension materials on a Leander Butler who served in Company B of the 10th Kansas Volunteer Infantry. This Leander Butler was born in the 1840s in Canada and lived for a while in Michigan. He's the Leander Butler in which I have a genealogical interest.
There's another Leander Butler who lived in Monroe County, Michigan, and was also born in the 1840s. He also was in the Civil War. I've eliminated them as being the same man as this Leander stayed in Michigan and served in a Michigan unit.
Of course, both Leanders are probable sons of different men named Benjamin Butler just to create additional confusion. If there's any relationship between them, I'm unaware of what it is and it's probably too far back to be overly helpful to me at this point.
The "suggested matches" on Ancestry.com likes to assume these to men are the same person.
I've already "sorted them out twice," because I neglected to write down my reasoning the first time.
I won't make that mistake again and it might even be helpful for me to put the reasoning in a blog post so that I can easily find it again if I need to.
And it might even help someone else on the same people.