2 advantages: underscore over dash

wells_planA is better than wells-planA

— Reason: click-to-select would select both parts as one word

works on all devices.

— reason: the underscore is a more visible delimiter of the two parts, and better resembles the space.

— reason: in short title for a file or blogpost, I often use q( + ) or q( = ). The dash becomes confusing.