Our house has wooden window frames divided into small panes. We repainted and repaired them 2 years ago, but the paint is already peeling off again and they're in bad condition. The problem is that the cowboy who converted this place didn't bother priming the wood before painting. So even though we carefully sand and prime any raw wood that's showing, we're not solving the underlying problem. What on earth do we do? We can't afford to replace the windows. We can't afford to have them painted every two years by someone else, and with small children we can't afford the time to paint them every two years. With the small panes, there's no way we could sand them all down and start again.
Paintstripper might work faster than sanding them all down. It might be worth tackling it one window at a time, so setting yourself a target of doing all of them in the next year to 18 months. Very boring job though, you have my sympathies.