We're moving into a wood home we bought. I'm considering having some kind
of metal or vinyl siding put on it, and need some thoughts as to how that
compares with painting.

What's a good range for how many years a house can go between paintings?

I've got an estimate of cost of painting, and an estimate of siding cost.
What's missing is how often we'd need to paint in order to do a long term
cost comparison.