Water around a skylight

Not necessarily. Flashing above the unit, the roof covering upslope, ice damming, and condensation on cold glazing all produce the same symptom. When it appears is what separates them.

Condensation appears in cold weather with no precipitation, forms on the glass and runs down, and is worse when indoor humidity is high. A leak follows rain or a thaw. If it happens on a clear cold night, it is not a leak.

Consider it seriously if the units are well into their service life. Reusing an aged skylight under a new roof is a common cause of a leak in an otherwise sound roof, and doing it later means opening the new roofing.

Often yes, if the unit itself is sound. It requires opening and properly restoring the surrounding roofing so the flashing is integrated rather than surface-sealed, and the manufacturer's kit for that specific unit should be used.

Usually because the shaft is not insulated and air-sealed where it passes through the cold attic. That makes it a condensation surface and a heat leak, and it can feed ice damming on the roof above.

As a standalone fix, no. Sealant has a limited service life and a joint depending on it alone will fail again. Correct flashing is a layered assembly integrated with the roof covering.

Skylights have their own service life, generally shorter than a roof's, because the glazing seals and gaskets age independently of the roofing. It is realistic to plan for at least one skylight replacement over the life of a roof, not to assume it lasts unchanged.

Yes — repeated dripping condensation running down interior trim or a wall can eventually stain, warp, or promote mold on nearby finishes even though the source is condensation rather than a structural leak. It is worth addressing rather than tolerating.

A skylight's own geometry affects how well it sheds water and debris — a flatter profile can hold water and debris longer than one with more pitch or a dome, though correct flashing installation matters more than the glazing shape for most leak causes.

A larger skylight has a longer flashing perimeter, which means more linear feet of detail that has to be correctly executed — more opportunity for a flashing defect, though not an inherently higher risk if the installation is done correctly.

Yes, this is a legitimate option when a skylight is failing and not wanted, though it involves reframing the roof opening and matching interior finish work, not just closing the exterior. Discuss it as its own scope item if being considered.

This does not affect leak risk, since the flashing and glazing are what keeps water out regardless of interior coverings. Closing shades is a comfort or privacy choice, not a protective measure against a leak.