Mosman houses tend to be older so many have sash windows (those old double hung windows where each panel slides up and down). Sash windows were invented in the 17th century in Holland … or France … or England - take your pick.
The beauty of a sash window is that it is designed from the beginning to be repairable. The flexible cords will eventually break so access is made easy.
My oldest sash window repair must have been close to 130 years old. Apart from the cord, all the parts were still working well. It’s hard to imagine a building product today that will still be working perfectly in 13 years time, let alone 130.
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