There are some general post-op rules following breast augmentation. There are also some surgeon-specific rules (they can advise different things!) and the more specific, tailored-to-you rules. If your breast implants don't settle into their pocket by themselves, then you might need some assistance.
We don’t 100% know the answer to some breast augmentation recovery questions because advice is based on either evidence (what we know works) or experience (what we have found to work). Some of the questions you ask won’t get a unified response. Some of the common bra recommendations have sensible reasons behind them though.