I don't even really think about it, I just comment if I have something to say. At worst, nobody reads it and I was shouting into the void for a minute.
But the Lemmy userbase isn't massive yet, so those week+ old posts still see more engagement than you'd think.
So far, we have a captcha on account creation now and it seems to be working (from what I've seen, anyway)
It'll be a tough balancing act though. Relatively frictionless sign-up has been great for us, and anything that deals with bots will also affect that. Whatever else we may end up doing will need to be carefully considered.