The 'how often' question gets endless conflicting advice, most of it missing the point. The real rule isn't a number — it's whether each email is worth opening. Frequency only becomes a problem when the value drops.
Send as often as you're useful
If every email teaches, entertains or genuinely helps, people happily hear from you weekly or more. If they're thin filler, even monthly feels like too much. Judge the value, not the calendar.
Pick a rhythm you can keep
Consistency beats intensity. A steady note every two weeks that you actually sustain builds more trust than a daily blitz that burns out in a month. Choose the pace you can hold, and hold it.