Why would a chipped tooth need filling?

[NervousUSA]

Hello,
My dentist said that my premolar is chipped, and might need a filling in the future. There is quite a big visible chip. What would be the sign that a filling was needed? Would is start to decay?
Thank you for your time!

 

[Gordon]

If it started to decay then it would be time to look at filling it.

 

[NervousUSA]

@Gordon Thank you for your help Gordon!