If a player's hat flies off, is that a hindrance? If the ball hits a tree branch, do you replay the point? Be knowledgeable about phones ringing, sticks falling, and birds flying overhead.

My opponent wants to watch an important match that is streamed live during our match. He said he\'d only watch it during changeovers.

Are players allowed to watch tv during change-overs?

No. ITF Rule 30 Comment 30.1 states "While on court or during a match, a player may not receive information via electronic devices. . . " The player should put their phone on silent and enjoy being on the court, engaged in their own match. If the televised match was important, they could record it and share it with their competitor after the match !