You have gotten most of the info here already but I will add the following:
IBKR will send you an email to warn you - hopefully prior to you going over the threshold. I worked with someone who designed the warning in the following way.
If there are 20 trading days in a month (Like Jan). Then your limit would be 7800 orders for the month. Once you reach the 75% threshold (5850 orders), IBKR will send you an initial warning via email. They will then also send you a second warning when you hit the 90% threshold (7020). The only issue is that the warning will come on the business day following the day you go over around 8 PM EST. So, if you go over on a Wednesday, then you will get the notification on Thursday night. Not perfect but should be okay for most.
Also, I'd rather not get into this here - but counting orders is not as easy as one may think. So - who knows - you may not be over. And you should be able to ask for your order count if you're really worried.
the email will look like the following: (Dec 2021 had 22 trading days)
Subject: FYI: Professional Customer Status
Dear Client,
This notice is intended to assist with monitoring your U.S. option orders for purposes of the
Professional Customer designation. As background, the option exchanges require any retail customer who submits over 390 option orders contracts on an average daily basis for a given month to be designated as a Professional. Professionals are then treated the same as broker dealers for purposes of execution priority and transaction fees in the following quarter.
Based upon a review of your activity in U***** and any related accounts for the month of Dec 2021, you’ve submitted orders totaling 6719 contracts, representing a daily average of 354 contracts through 28 Dec 2021. Based upon this data, we project that you will meet the Professional classification if your total orders for the remainder of this month exceed 1861.
For additional information on this topic, please see
KB1242 Priority of Professional Customer Orders.