You should wear each aligner for 20 to 22 hours a day for the best results.
No, you can eat what you want since the Invisalign aligner are removed when eating or drinking. Just brush and floss after meals before reinserting the aligners.
Only drink cool water while wearing aligners. Hot beverages can warp them, and other drinks can cause cavities or stains.
No, gum can stick to the aligners. Remove them for all meals and snacks, including chewing gum.