When we bought the house 3 years ago the previous owner had records of everything they had checked and serviced every year. The furnace was one of them there’s a sticker on the side of it where it’s been signed off by the tech that came and checked it over and changed the filter every year.
bought the house in 2020 it was built in 1820 so it’s a old solid built house. The previous owner was a lawyer and the old police chief of the town so he had $$$ the roof was done in ‘18 water tanks(2 of em) were swapped 07/09 so they are fairly current I suppose. The furnace was new back on 07 I think it said it was installed. All the upkeep on the house was documented and done but they did nothing to update the house looks wise just the necessities roof, furnace, gas fireplace, electric heaters in the addition, hot water tanks, basement ect. But it was still rocking the old shag carpet in some rooms and ugly floral wall paper haha.