Why flea logging wants a row per application
A checkup spreadsheet can hold one row per cat, updated yearly, but flea prevention generates a steady stream of events, and squeezing them into a single cell per cat produces an unreadable tangle within a few cycles. The structure that stays clean is a log: one row for every application, added at the bottom as it happens. Columns stay small and consistent: date applied, cat name, who applied it, next due date for that cat, and a short notes field. Sorting or filtering that log by cat instantly reconstructs any individual's full sequence, and sorting by next due date shows the household exactly what is coming up and what is overdue.
The shared check that stops double treatments
The most valuable moment in this system happens before a treatment, not after it. Because the spreadsheet is shared and current, whoever is about to treat a cat opens it first and reads that cat's latest row: the date of her last application and who did it. That ten-second check is what prevents the classic two-partner accident, in which a cat is treated on consecutive days by people acting in good faith on stale information. For the check to protect you, logging must be immediate: the person who applies a treatment adds the row the same evening, from their phone, before the fact has a chance to become a rumour.
Notes that make the log clinically useful
Use the notes column for the small facts that later explain a sequence: treated three days late because the cat was at the vet, mild redness at the application site the following day, product changed on veterinary advice, cat stayed with a sitter who applied it. Written at the time, these entries let a vet reviewing the log distinguish coincidence from pattern, and let your partner understand a gap without interrogating you. Keep notes to a phrase. A log that demands essays stops being updated, and an abandoned month in a flea log is worse than a sparse one, because later readers cannot tell missed treatments from missed entries.
A monthly sort keeps the shared sheet honest
Once a month, sit with the sheet together for five minutes and do three sorts. By next due date, to see what falls in the coming weeks. By cat, to confirm every cat's rows arrive at the expected rhythm with no silent missing cycle. And scan the who-applied column, which quietly reveals whether one partner is carrying every treatment and whether handoffs are being logged at all. Any row that should exist and does not gets added then, marked as a late entry with the true date, while memory can still supply it. That monthly reconciliation is the difference between a spreadsheet that describes reality and one that merely hopes to.
Rows summarise; the cat still needs her documents
A shared log proves dates between the two of you, but third parties ask for more: a vet wants the product history in context with vaccines and weights, a boarding facility wants evidence presented as the cat's own record, and a new owner would need the whole story transferred intact. Keep the spreadsheet as the working log you both maintain, and hold each cat's underlying record in a form designed to be shown and handed over. When the log needs to become proof somewhere else, KinsLe Pet Passport presents this cat's history as her own standing record, ready for a surgery, a boarding desk, or a future owner.