When to replace your car seat: height, wear and tear, and buying a second-hand one.

When to replace your car seat: height, wear and tear, and buying a second-hand one.

Replacing items "at the right time" is just as important as buying the right ones. Children grow, their needs change, and some chairs become unusable sooner than they seem.

1) Indicator #1: Height outside the chair's limit.

With R129 / i-Size, the limit is by height .

Change when:

  • The child exceeds the maximum limit (e.g., 105 cm, 150 cm, depending on the model).

  • The head starts to sit too high (depending on the type of chair/backrest).

2) Indicator #2: Harness stops fitting properly

If the harness:

  • It doesn't rise enough anymore.

  • It's too short even when properly fitted.
    … it's time to move on to the next phase.

3) Indicator #3: wear and tear, fall or accident

Replace (or at least have it checked) if:

  • the chair was in an accident (even a "minor" one)

  • There are cracks, broken pieces, and deformations.

  • The base/ISOFIX no longer locks in place like it used to.

4) "Shelf life" and aging of materials

Plastics and foams age with:

  • heat, direct sunlight, temperature variations

  • Heavy use and aggressive cleaning

Even without a simple legal "deadline," common sense dictates:

  • Avoid very old chairs.

  • Follow the manufacturer's recommendations.

5) Buying a second-hand car seat: when is it a bad idea?

It's risky if:

  • You don't know the history (accident/fall).

  • missing homologation label

  • parts are missing (gearboxes, guards, manual)

He points out that since 2024, the market has begun to favor R129/i-Size in retail.
For a safe purchase today, it makes sense to look for UN R129 and a verifiable history.

6) How to make a safe purchase (quick checklist)

  • UN R129/i-Size Label

  • Original manual / clear instructions

  • No structural damage

  • No gaps in the ISOFIX/base

  • Known history (ideally invoice/store receipt)

FAQ

When can a child stop using a car seat?
When the Portuguese rule no longer applies: <12 years and <135 cm requires an approved system.

Can the R44 still be used?
The standard was gradually replaced in the market by R129; retail switched to R129 starting in 2024.