According to the product label for Avid 0.15 EC Miticide Insecticide, "For mites, apply when mites first appear and repeat as necessary to maintain control." For more specific recommendations on ideal application timing for spider mite eggs, we advise contacting your local county extension office.
Avid 0.15 EC Miticide Insecticide has a shelf life of 3-5 years from the purchase date if stored in a cool, dry place (away from extreme temperatures).