Why do we need to retrain models and how often?
It is very important to make sure that your model is reflecting reality as much as possible. Retraining your model is how you keep your model up to date and ensure that the quality of your model production doesn’t degenerate. Retraining is also done in order to avoid data drift and or when you notice it.
How often you retrain your model depends on a case-to-case basis. You might need to retrain it periodically or at intervals, it could be a performance-based trigger, based on data changes or on-demand. It is imperative to include retraining in planning.