A quiet trap for bots
Add one hidden field to your form. People never see it; many bots fill it. Those messages are kept aside while the bot receives the same polite response as anyone else.
<input type="text" name="_gotcha" tabindex="-1" autocomplete="off" style="position:absolute;left:-10000px" aria-hidden="true"> <input type="text" name="_gotcha" tabindex="-1" autocomplete="off" style="position:absolute;left:-10000px" aria-hidden="true">
A little breathing room
Set a sensible pace for each form and say which sites are allowed to post. A sudden rush or a post from somewhere else is kept aside with a reason instead of landing in your inbox.
A stronger check when you need it
Turn on Cloudflare Turnstile for a form that is getting extra attention. If the check cannot be completed, Postbag keeps the message aside rather than throwing it away.
Useful labels, not permanent verdicts
You can review what was caught and mark a real message as not spam. Your inbox never sees the noise by default; a full record can include everything when it truly needs to.