There is no one-size-fits-all answer to how often contact databases should be cleaned. It’s a decision that depends on your specific circumstances and priorities. Like for instance, according to the business needs - is it for marketing, sales or the like then regular cleaning is required to maintain data integrity. Some industries might also have data standards so accordingly data is cleaned following the legal obligations. Regularly assessing the quality of your data and the impact of outdated information on your business to determine an appropriate cleaning frequency.