It changes regularly, and by significant amounts. Magnetic north can drift 45km to 55km per year, and in the article it was talking about a major airport in Canada, the Calgary airport, where even slightly out of date maps were off by as much as 7°. Source: https://www.ncei.noaa.gov/news/tracking-changes-earth-magnet...

Will it require repainting? Probably not, but the further north you go, the more noticeable even minor drift or fluctuations will be.