It is better to stick one. The film is used to protect the film.
It is not necessary. It ridiculous to say that the film can resist radiation. There is no film can resist light radiation unless the film that is made of lead metal. The plastic synthetics of the film contains radiation itself. General film is mainly used to protecte a screen and prevent scratches and dust, but it affect the appearance. Besides, many hard screen do not need the film. Go to check whether your screen is soft or hard. In other words, you can check whether there is water wave when pressing the screen. If there is, the screen is soft and whether sticking the film or not is acceptable. The film is not necessary for hard ones. As for me, it is a waste of money to stick the film.
No, the film is not necessary. The film affect the appearance of the sccreen. It seems to have no effct on heat dissipation. To clean the screen, you can just buy a cleaning kit. If there is lot of dust, you can use the hairbrush to brush it. If there is liquid stain, you can clean it with the cleaning agent. It will not cause any harm to the screen if it is not cleaned for a long time, but it may not be pleasing to the eye and it will take more time and energy to clean it if the dust piles up. The water stains is difficult to be remove when they have existed for a long time. The screen should be cleaned lightly as the LCD can not bear pressure. You should try not to poke the screen with your fingers.
