When is isolated sheathing damage small enough to handle separately?

A small section of damaged roof sheathing can sound like a limited repair, but removing it opens the roof and may reveal damage beyond the panel itself. How do the size and location of the affected area, and the condition of nearby rafters or trusses, change the point where a roofer should take over?

I’m also curious how people judge whether the work can be sequenced safely with temporary weather protection, rather than leaving the opening exposed if conditions change. What signs suggest the framing or surrounding roof needs a professional assessment before any sheathing is removed?