I changed mine once under NTUC insurance $0 excess.
They are two type of Windscree, with or withoud the sunshade on the top part. The workshop guy told me our windscreen is 3 layer glued together so when it crack, the whole windscreen still hold together.
If it crack a little, the temperature (and the pressure) different between cabin and out side will expand the crack. If water and dirt gets into the crack it will expand too. I had to wait a few "weeks" for the workshop to get the windscreen with sun shade, so I stick something outside windscreen to prevent water/dirt gets into the crack and wind down the window a bit while waiting for parts. The crack line is about 5cm and did not expand much after a few weeks. If only I can go to any workshop, I can get it fixed in days.
$0 excess

NTUC increse my premium the next year enough to pay for the windscreen! so I changed to another insurance company.