Clipping up a mirror means you can remove it easily in the future. Glued up or floating mirrors are harder to remove and may damage the wall upon removal.
No, glass only replacement is usually available and less expensive. If your window frame is damaged, an entire window may be needed.
Yes. A protective coating that penetrates into the pores of the glass to create a sub-surface is available on new glass. It may be used on existing glass but since the pores have already been damaged, their is no guarantee it will work.
Annealed glass or float glass is the basic form of all glass. When broken, annealed glass will shatter or break into large fragments. The thicker the glass, the more dangerous the fragments. Safety glass or tempered glass is glass that has been processed by a heating it to make the glass stronger. When broken, tempered glass will shatter into small fragments, making it less likely to cause severe injury. Another safety glass is called laminated glass. Laminated glass is when two pieces of float glass are bonded together to keep the glass from breaking apart. Laminated glass is typically used in auto glass. All shower doors, by most building codes, must be tempered and must display the tempered stamp or “bug” somewhere on the glass itself. The “bug” will also display the name of the company who tempered the glass. This may be different from the manufacturer of the shower door but is still a reference when determining where the door came from.
Great question with a not so great answer. Shower door manufacturers are terrible at putting their name on their product. Most manufacturers buy their glass and metal from different suppliers. The best place to get parts for your door is from the company your purchased it from. If you are building a new home, be sure to keep a list of suppliers where your builder received his products from. If you don’t know where your shower door was purchased from, then may the luck of the Irish be on your side. Taking a picture of the part you need and calling/visiting local glass shops would be your best bet. I can look at a part right away and tell if it came from our shop or not. Sometimes, parts can be interchangeable, but not always. Spending the small amount of money to give it a try can sometimes be better than buying a whole new door.