In general, the tempered glass screen protector after using for a period of time, the AB adhesive layer has been attached on the phone screen already, when tear off it, the absorption will be weakened. At the same time, the glue side will get dusted in the air, which affects the exhaust effect. So a tempered screen protector is not recommended for secondary use.
If the film and the screen was misaligned when stick it at the first time and needs to be re-stick, it is recommended to quickly uncover the film and align to the screen to stick it again in a relatively clean environment. If have dust attached, can remove it with a dust remover. Therefore, it is best to thoroughly clean the screen before the first sticking the screen protector, to avoid the risk of secondary film sticking.