If storing the whole head of roasted garlic, it will last about 4 days in the refrigerator. Keep it sealed in an airtight container. You can also squeeze out the individual cloves into a jar and cover them with olive oil. Those will keep in the fridge up to 10 days, since the olive oil seals them away from contact with air. Be sure to cover the jar with a lid and it must be kept in the refrigerator, not out on a counter.