How long a joint really lasts (bath, kitchen, window)

It is not a use-by date

Silicone does not “expire” on a Tuesday. It loses plasticisers and polymer to heat, soap, chlorine and UV. It goes hard, stops following the substrate and opens or peels. A decent cartridge lasts longer; a filler-heavy one, less. Use beats the label.

The spans below are orders of magnitude, not a guarantee and not a company slogan.

By room, from the job

Shower and wet zone. Often 5–8 years. Soap, skin grease, heat, limescale cleaner. Signs: peel at the tray, mould in the mass, rubber that no longer springs back.

Kitchen worktop. Often 8–12 years if it is not behind a hob that fries. The enemy is grease and heat. It yellows or opens on the back edge.

Windows and glass outside. With a proper glazing sealant and a joint that can move, sometimes 15–25 years. UV and thermal cycling mark it. Crazing or a dusty face: it is finishing.

Movement joints in floors or façades. Often 10–15 years, depending on movement and chemistry. A split down the middle: cohesion; the rubber has nothing left.

When to replace and when to wait

Replace if it has peeled, if there are black specks in the mass, if it is hard like plastic, or if there are hairlines in the corner of the bead. Wait if it is only dirty or a bit yellow and, pressed with a nail, it springs back.

Raking light shows open edges. The nail tells you if it is still alive.

What shortens it

Chlorine: kills fungicides and the rubber. Acrylic in the shower: not for standing water. Over old silicone: months, not years. No primer on a substrate that needs it: it opens in a couple of years. Three-sided adhesion without backer rod: life is halved.

A professional silicone (I use OTTOSEAL in the wet zone) carries fewer fillers; it stays elastic longer. It is not magic: leave it in a puddle and it still fails.

Clear shows more of what sits behind it; colour itself barely changes life.

Exceptions

A neighbour on 10 years and you on 3: almost always cleaning chemistry, ventilation or a badly designed meeting, not “bad luck”. Inspect; do not wait for the stain on the ceiling below.