During what construction era was plaster installed over metal lath?
The area I live and work in saw quite a bit of expansion and development in the period between 1920 and 1960.  I see plaster over expanded metal quite a bit in older buildings, and it does present some challenges.
My guess based on what I've seen is that it was used mostly in the 1930s, 40s, and 50s, and more in commercial and multi-family buildings than in residential construction.