If your matcha has lost its vibrant green color, that's a sign it's oxidized and past its best. If it's clumping or smells stale, it's time to replace it. Also, if you're finding your drinks taste bitter or flat, it might not be your technique—it could be old powder. Keep an eye on the harvest date, not just the best-by date, and buy from a source that rotates stock regularly.

Another sign: you're using the same grade for everything. If you're mixing ceremonial grade into smoothies, you're probably wasting money. And if you're drinking culinary grade straight and finding it too bitter, you might be better off with a higher quality culinary or even a mid-tier ceremonial. Matching the grade to the use is the key to getting your money's worth.