Of course, once a month is too little – the weeds have now taken root and could hurt your other plants when uprooted.
Many things in life require similar “weeding” – a great example is email. If you check it every 5 minutes, you’re wasting time not to mention switching mental gears WAY too often. But (for me) once a day would be rough because I’d miss timely emails and have to set aside an hour or two to wade through the messages.
For each person, therefore, it’s different. But the concept is the same: some things require often “weeding” while other things don’t – I could probably go through my snail-mail once a week and be fine. I recently put a hold on my main for a month and it was fine when I got it all.
Seriously, no mail for a month. And an additional benefit of that is they typically only hold first-class mail which means they filter out the junk mail for you!
What in your life could benefit from doing it less? What do you need to do more often?