We purged 32k unverified bot/spam accounts from our Lemmy instance this past week. We had email verification on but had missed adding CAPTCHA during initial setup. We're still fairly new. Had over 1500 accounts "apply" within a 2 minute span. My admin email was flooded. It was ridiculous.
They're gone now, but we're staying vigilant.
We go maybe twice a month. We have to go down and cross the border into Oregon to do it, so we don't do it that often. They have a few things that we just won't do without. My husband loves the muffins, has one every morning for breakfast.