How do I know if I need to change my screen

Here are some questions you can ask yourself while looking over your phone:

• Does the glass have visible cracks in it?
  • Are the cracks interfering viewing the LCD?
    • Are the cracks spider webbed and rendering the LCD very unviewable? Yes, replace the screen.
    • It is only a few cracks: 1-3? Maybe, depends on how annoying it may be to you.
  • Are the cracks not on the LCD? No, deal with it for now unless it becomes a problem then replace it later on.
• Is the LCD broken and areas either blacked out OR are there vertical distorted sections? Yes, replace the screen.
• Does the digitizer not react to areas you touch on your phone? Yes, replace the screen.
• Are areas of your LCD not as bright as others? Maybe, this depends entirely on you and if the % of dimmed screen is annoying to you or not.
• Are there a great number of scratches and scuffs on the screen? Maybe, this depends similar to the above question and the % of the glass that's scratched and scuffed up, also how badly the glass is damaged.

Hopefully this will answer your very vague question regarding if you need to change your screen or not.