I read my mom's copy of King Lear when she was studying it in college before I read the play myself. This turned out to be a really useful experience. By looking at her notes and annotations, I was able to gain a deeper understanding of the characters' true motives and attitudes toward one another. It was like having a guidebook to the play, which helped me to see things that I might not have noticed otherwise.
For example, I was able to see how Lear's pride and stubbornness led to his downfall, and how Cordelia's honesty and loyalty were ultimately her undoing. I also learned about the complex relationships between the other characters, such as the rivalry between Goneril and Regan, and the loyalty of Kent and Gloucester.
Overall, reading my mom's copy of King Lear was a great way to prepare for reading the play on my own. It gave me a head start and helped me to appreciate the depth and complexity of Shakespeare's work.