I have never ever needed to change even one bulb for such switches in any car I have owned . With so many not working have you checked its not a common cause that affects them all ? Maybe a blown fuse or a wiring loom connector block loose .
Try removing one of the bulbs and checking it visually ,or with a multimeter, to see if it really has blown. Or try fitting the bulb from another switch that is known to be working to see if it now works.