Roofs rarely fail suddenly. They give you a long warning and most of it is visible from the ground, if you know what you are looking at.
Sandy grit in the gutters
Fine mortar debris collecting in the gutters is bedding mortar breaking down under the ridge capping. It is the earliest sign you get, and at that point the fix is routine repointing.
Cracked or lifted ridge capping
Visible cracks along the ridge and hip lines, or capping that has visibly shifted. Coastal weather shortens the life of bedding mortar considerably, so this is normal maintenance rather than a sign of a bad roof.
Slipped and broken tiles
Individual tiles out of line are easy to see and cheap to fix. Left alone, the gap lets water onto the sarking and eventually past it.
Stains that appear away from the leak
Water runs along battens and rafters before it drops, so the mark on your ceiling is often metres from where the water actually enters. This is why patching the ceiling never works.
What we cannot help with
If the problem is your gutters or you have a metal roof, that is roof plumbing in NSW and legally requires a licensed plumber, whatever it costs. We work on tiled roofs and will refer you on if yours is not.
Want a hand with this at your place? Get a free quote or call 0450 959 936.