Look for movement
From the ground, check whether any slates, tiles or ridge pieces sit out of line. Compare both slopes if you can see them. Fresh movement often catches the eye before it becomes a leak.
Clear drainage routes
Gutters and visible outlets should be free of moss and leaf debris. Summer is also a useful time to deal with plant growth around flat-roof edges before autumn rain arrives.
Revisit old stains
If you had a winter leak, check whether the internal area is fully dry and whether any musty smell remains. Old staining can be redecorated once you are confident the cause has been dealt with.
No need to walk the roof
Most homeowner checks can be done from ground level or through a loft hatch. Walking on tiles or slates for a “quick look” can create damage that was not there before.