Does an ISOFIX base expire separately from the infant carrier?

Why is the base not "the seat"?

A click-on infant carrier is one approved child restraint. The ISOFIX base is another moulded product: ISOFIX arms, support leg, indicators, sometimes a rebound bar. Families often keep the base in the car and buy a new carrier for baby two. That only works if both still sit inside the years and the compatibility list in the current manuals.

GOV.UK requires an approved child car seat with the right E-mark. It does not print one shared expiry for a carrier-plus-base pair. Child Car Seats tells you to check the manufacturer's advice about how old the restraint should be before replacement — for a two-part system, read both parts.

This page is not a second-hand buying checklist and not a recall walkthrough. It is about whether the base has its own clock.

What have UK brands said about base years?

RoSPA states that UK seats are not marked with an expiry date. "Developed for intensive use of about X years" is manufacturer language, not a Highway Code use-by date.

How do I check the base and the carrier as two clocks?

1. 1
   Photograph the carrier label Model, serial, manufacture date. For Joie seats use the Joie seat-label guide.
2. 2
   Photograph the base label Usually on the underside. Maxi-Cosi UK care and later Which? reporting both treat the base stamp as its own week-and-year or printed date. Decode a four-digit Maxi-Cosi code with the week-year guide. For Joie bases use the Joie base page.
3. 3
   Open two current PDFs Carrier manual and base manual (or the combined booklet if Joie / Maxi-Cosi still ship one file). Write down each "years" sentence and its start point.
4. 4
   Check the compatibility list A new i-Size carrier may not be approved on an old FamilyFix. Years left on the base do not create a pairing the booklet never listed.
5. 5
   Treat a crash as stopping both The 2017 Maxi-Cosi UK reply said seats and bases involved in an accident should be replaced immediately. Joie's UK FAQ says the same for seats. The year count does not reset.

Can I keep the base for baby two and only change the carrier?

Only if the current base manual still lists that new carrier, and the base is still inside the years sentence that booklet prints today. A 2017 "about 10 years" email does not override a later 6-year line on a different Maxi-Cosi base. A Joie i-Base Encore does not inherit the i-Base 5-year purchase sentence unless its own PDF says so.

If the base history is unknown — bought separately, inherited, or missing a date — Child Car Seats already advises against a restraint whose history you cannot be certain of. The carrier being new does not give the base a new history.

In shortThe base has its own stamp and its own years. Maxi-Cosi UK has used about 10 years in an older care reply and about 6 years on a later official base PDF. Joie may cover carrier and base in one purchase-date sentence. Official records do not print a single shared expiry. Read both current manuals; do not invent a year.