If you opt for a dual coffee maker with a built-in grinder, it may not be necessary to purchase a separate one. However, it's essential to consider the type of coffee you prefer before making this decision. Some machines come with grinders that offer limited customizability in terms of grind size and consistency, resulting in coffee that is either too weak or too bitter. If you value customization and precision over convenience, investing in a high-quality burr grinder alongside your coffee maker might be worth considering despite its higher price point.