Co-Pilot is constantly learning, the algorithm that helps drive the Recommendations Model for your specific Stack only updates (or "retrains") weekly by default. Retraining incorporates any new insights that have been captured within the previous week, including any changes in user behaviour and/or identification of trends.
Model retraining frequency can be changed to monthly or a manual retrain initiated on the Co-Pilot settings screen by navigating to Settings > Co-Pilot.