Just got a merge request where the individual was clearly the same but the parents were different. Since it's always best to resolve the parental (and grandparental) issues first and work down, I took a look and did some research on WikiTree.
One problem causing confusion is that hundreds of years ago nobody cared how they spelled the name. So we have "i" or "e" in the first syllable, an "i" or "e" in the second syllable, one or two "l"s, in the third, and an "a" or "y" in the last. Trivilian, Trivelian, Trivillian, Trevilion, Trevelian, and Trevelyan.
These can be merged into one LNAB, but which? And although I hate clutter in the data field, it feels like to avoid more duplicates in the future, we'll probably need to list the alternatives under "Other Last Names"
John R. Carpenter, an expert on the Carpenter family which descended from it, posted a G2G note about the family in 2013 -- and spelled it two ways in his note (Trevelyan and Trevelian). I sort of like Trevelyan with a "y", but the decision probably should be based on what's used most often, or some other logic other than whim!