Customer retention means how well a business keeps people buying again after the first purchase. It is about building a steady relationship instead of chasing new buyers every time. When customers stay, they already trust the brand and understand the product, so they buy with less stress. This matters in digital marketing because online choices are many and switching is easy. Retention saves money, brings stable sales, and spreads good word through reviews and sharing. A business that keeps customers grows slower but stronger. How important do customers seem online?