Nuts contain oils that can develop stale or rancid flavors. A decorative jar next to the stove is an attractive place to forget that heat matters.
Follow the packet's storage instructions and keep nuts well sealed. If you buy more than you use quickly, refrigeration or freezing in suitable airtight packaging can help preserve quality. Label the contents, especially if several chopped nuts look similar.
Taste or smell a small amount before adding nuts to a whole batch of food, while remembering that sensory checks do not replace safe storage. A stale handful can dominate a mild sauce or crumble. Keep separate utensils and clear labels when cooking for people with allergies; moving nuts into an unmarked jar makes ingredient checking harder, not easier.