Write it down on the day, not from the empty packet
The reliable moment to record a flea or worming treatment is the minute it is given, not weeks later when you find an empty packet in a drawer and try to reconstruct the date. Note the day, what was given in plain terms, and any reaction you noticed afterwards, such as scratching, sickness or unusual quietness. A note made at the time captures the reaction detail that memory drops first, and that detail is exactly what your vet will ask about if a later treatment needs rethinking. Photograph the packet beside the record book on the day if loose scraps tend to vanish in your house; the photo is only a backup, while the written entry remains the version everyone works from.
Work out the next due date at the same sitting
Do not leave the interval to be calculated later. While the packaging and the product's own guidance are still in front of you, work out when the next treatment falls due and write that date beside the entry, then set a reminder for a few days before it. Flea and worming schedules rarely run on the same rhythm, so keep two separate running lists rather than one merged note; a merged note is how a worming date gets mistaken for a flea date and a treatment quietly doubles or lapses.
Keep the list on the dog's record, not a disposable calendar
Wall calendars get replaced, phone notes get deleted, and the treatment history is lost with them. Keep the running lists inside the dog's main health file, alongside vaccination records, so the history survives the years and can be shown whole. That complete view matters: a boarder may ask when the last flea treatment was given, a new vet will want the pattern rather than the latest date, and a gap you can see on paper explains a flea problem far faster than guesswork.
Watch the pattern, not just the latest entry
Read back over the list every few months. Lengthening gaps often reveal that a busy season, a house move or a new baby pushed treatments late, which is useful honesty rather than failure. If fleas keep appearing despite treatments recorded on schedule, or your dog reacts badly more than once, take the full list to your veterinarian instead of simply switching products at home; the dated pattern helps the vet judge whether the issue is timing, coverage of bedding and housemates, or the treatment itself.
Make the next person able to continue the list
Write entries so that a partner, adult child or sitter could pick the file up and give the next treatment correctly without phoning you: plain product description, where it is kept, and the due date in full. If someone else gives a treatment while you are away, ask them to record it the same day in the same place. Logging each flea and worming treatment through Care Teams on KinsLe gives every entry a timestamp and a named person, so the due dates stay visible to the whole household instead of living in one person's memory.