Can Parting Your Hair Lead to Damage?

Hello Dr. Rassman,
Couple of questions for you.

1. whats the average length of a horizontal hair line above the temples. I know everyone is different, but just an average length for someone in their late 20s to mid 30s.

2. can parting your hair to one side for years with hairspray or gel cause any permanent damage to that specific side.

The length of the hairline where the hair point forward in the front is about 5 inches. The hair normally parts a certain direction in most people and creating or forcing it to part in a different direction will not damage the hair.