When encountering temporary errors from Yahoo, a nuanced approach to retries is crucial. While RFC5321 suggests retrying for 3-5 days with a backoff, this can exacerbate issues during Yahoo's TSS errors. Implement a 4-hour delay, not exclusively for retries but for all delivery attempts. If Yahoo is deferring, slow down sending significantly or halt it altogether. Mail servers usually retry for about 5 days, although this varies. It's important to maintain a proper email deliverability strategy, segment lists, handle soft bounces, and avoid overwhelming the recipient server to protect sender reputation. Documentation indicates a 24-hour retry window for some providers. Ultimately, balancing persistence with caution and adapting to Yahoo's signals is essential.