I ordered a pack of 6 Frontline plus for dogs in mid October and, because I had to register my dog's details, the company knows I have only one dog. The use by date is July 2022. If administered every 8 weeks starting immediately, it would be the end of July before the last one is used, which doesn't give any leeway on timing. I have one phial still to use up, which will mean throwing one from this order away, so they're not such good value for money as they appear. I've never received such a short use by date from any other company and I've been using Frontline for many years.