Don’t touch the glass when changing the bulbs.
When you change a bulb in your car and you touch the glass part with your hand, you will most likely leave some dirt and oil residues on the glass. It may cause that part of the glass gets hotter than the other parts when your lights are on, causing stress inside the material. After some time, the wear may cause damage in the bulb and require you to replace it with a new one. That is why you should always keep the bulb by the metal part when replacing the glass bulbs.