Do I really need to grind my own coffee?

Pre ground coffee starts losing flavor compounds within 15 minutes of grinding. After a week, it has lost the majority of its aromatic oils. If you buy whole beans and grind before each brew, you will notice a significant taste improvement more aroma, more nuanced flavor, and fresher taste. This is the single biggest upgrade most coffee drinkers can make, and it costs less than upgrading your beans.