Snow removal from flat roof - NY Capital Region/Troy, NY

[Allison Keane Barr]

My husband and I are looking at buying our first investment property in Troy, NY - one of the flat-roofed, two-family homes that are so common there - and we want to understand what the needs and costs would be for snow removal from a flat roof. Anyone have experience with this? How often do you have to clear the snow? Do you typically hire a contractor for the entire year at a flat rate, or per instance? What do costs look like?

We saw in one article that snow on a flat roof can actually provide some insulation for the building, but not sure about how wise that is. Maybe safe to leave the snow there for longer on a newer roof?