History of mountain dulcimer
General mountain dulcimer or music discussions
Not sure exactly what time period we are talking here- during or before before Jean's time (b.1922)? Remember that the earliest mtn dulcimer so far that has been accurately dated was from the 1830s- actual mtn dulcimers may not even have been 'invented' before 1800.
I've always been doubtful about the conjecture that mountain dulcimers were commonly played for social dances or in church. I've never read any verified references of it, and it seems unlikely to me. On the other hand, many churches and most grange halls had a piano. And guitars, fiddles, and (to a lesser extent) banjos... were pretty widespread among the communities.

I'm normally pretty cheap about strings and only change them once in a while, not 'regularly'. The only strings I actually notice that 'die' over time are wound strings. The great Margaret Barry once said that in hard times she stripped wire from window screens to string her banjo with.
Just sayin'!