AED maintenance changes from brand to brand, and the manual writes the calendar.

Fire extinguishers have a technical standard that sets the months; defibrillators do not. No Italian, French or German legal text says how long a battery or a set of pads lasts: the manufacturer states that in the manual for the specific model, and the law — where it says anything at all — deals with something else, namely the maintenance record, the registration of the device and, in Germany, a periodic technical inspection.

That leads to the first useful distinction, which is about design rather than marketing. Some units combine battery and pads in a single cartridge — HeartSine's Pad-Pak is the clearest case — so there is one date to watch. Everything else keeps the two consumables apart: battery on one side, pads on the other, two dates that rarely fall in the same month and that you usually find out of step the first time one is replaced off-cycle.

The practical consequence lands on anyone with more than one unit. Two AEDs of different makes on the same site are two calendars, and neither one warns you about the other. On top of that sits the rule that holds for every brand: pads used on a person are replaced regardless, even if the date printed on the pouch is still years away.

HeartSine builds the samaritan PAD 350P, 360P and 500P around the Pad-Pak: a single cartridge holding both the battery and the pads, with a stated life of 4 years. It is the design that cuts human error the most — one date per unit, no combinations to remember — at the cost of replacing two components when only one is genuinely spent. A paediatric version exists too, with its own date: keep one in the cabinet and you are back to two dates.

ZOLL AED Plus goes the other way and carries the longest intervals in the table: type CR123 lithium batteries rated up to 5 years in standby, and CPR-D-padz — the one-piece electrode with the sensor that paces compressions — also at 5 years. It looks like "everything at five years", but the battery and the pads are still two separate purchases, and if the cabinet also holds the Pedi-padz II paediatric set rated at 2 years, that shorter date is the one running the calendar.

ZOLL AED 3 keeps the 5 years on the battery and on the CPR Uni-padz — the universal adult-and-child electrodes — and adds a display plus, on Wi-Fi versions, remote status reporting. Anyone searching for the AED 3 service manual is usually after exactly this: the administrator's guide ZOLL publishes for its models, which is the document a maintenance plan should be copied from rather than inferred from a similar unit.

Philips HeartStart HS1 and FRx run on the M5070A battery, rated for 4 years of use after installation — with an "install by" date to read before fitting it — while SMART Pads II stop at 2 years. That is the widest spread in the table: on the same AED, pads are replaced roughly twice per battery cycle. The FR3, the professional-range model, has its own consumables and has to be read off its own manual.

AMI Italia is the brand behind a steady stream of searches in French and Italian for Saver One maintenance, a range widely installed across southern Europe. Battery and pads have expiry dates stated in the manual for the exact version — Saver One, Saver One D, Saver One P — and they are not inherited from another make: here the table deliberately points at the manual instead of offering a number.

Three more units turn up often in workplaces. Cardiac Science Powerheart G5 states a 4-year Intellisense battery and daily, weekly and monthly self-tests flagged by the Rescue Ready indicator. Physio-Control LIFEPAK CR2 states 4 years for both the battery and the pads, with connected versions that report status remotely. Schiller FRED PA-1 runs on a long-life internal battery, but the manufacturer does not publish its documentation for free download: ask the distributor or the authorised service, and write the dates down on delivery rather than hunting for them online.

In France the record is an explicit requirement. The arrêté du 29 octobre 2019, made under décret n° 2018-1186, requires a registre de maintenance in which every intervention on the AED leaves a trace — who carried it out, the date, what was done and the outcome — and maintenance performed in line with the manufacturer's instructions; the unit must also be declared in the national geolocated database. Décret n° 2007-705 is often quoted here: that text allows anyone to use an AED, it does not impose the record.

In Italy the register exists, and so does the interval. DM 16 marzo 2023, the decree implementing Law 116/2021, requires the responsible person to record at least once a week the operating status of the AED, its battery and its pads (Annex A, point C.4): it is a legal duty, not good practice, and internal procedures should say so. Alongside it sits the duty with the hard date: Law 116/2021 requires the unit to be notified to the 118/112 dispatch centre with location, brand, model and consumable expiry — the 60-day term in art. 6 applied to AEDs already in service when the law came into force, while a new unit is notified at installation.

Germany inverts the order. Owning an AED is not compulsory — DGUV Information 204-010 is a recommendation — but on a unit already in service § 12 MPBetreibV requires a Sicherheitstechnische Kontrolle at least every two years, carried out by a technician qualified under § 5 and documented for five years. Lay AEDs with self-test installed in publicly accessible spaces are exempt, in exchange for the operator's continuous visual checks; from 1 January 2027, new lay units with self-test must also document the results and transmit them automatically to the operator.

Switzerland and Austria stay deliberately more open. Switzerland has no legal duty to own an AED, and maintenance follows the manufacturer's instructions, in line with the SUVA recommendation and the employer's general duty of care; some cantons — Ticino is the one usually named — are reported to require the unit to be announced to the 144 dispatch centre: check with your own centre before ticking that box. In Austria § 6 MPBV provides for technical safety checks on active medical devices, but the interval for AEDs is not uniform and follows the manufacturer's instructions: have the applicable interval confirmed by the authorised service rather than picking a date.