The monthly process isn't necessarily to renew domains - it is to assess the situation to see if there are any that need renewing soon. Many months nothing will need doing, a couple of months per year something will need action.

Even as a small company we have a number of regular infrastructure reviews. Most of the time we just go through the review, find nothing has changed unexpectedly and no new ideas need bringing to the table, we sign off to say all looks well, and the prices takes very little time. Some of this is automated: scripts collate and report information for signoff and we humans verify the result and take actions as needed (in some cases the action needed is to update the script(s)). This may seem wasteful, but a couple of people spending a couple of hours total per month on such checks can save some nasty surprises in future.

Domain status checks is one of the things that gets reviewed.

If you have multiple domains you could renew them at seperate times.

Has the advantage that a failure might not be so disastrous either.