I'm interested in buying an old rambling house in france which is a bit of a mix of this
and that added to at various times and without any particular attention to continuity in
the roof surfaces. Including 4 or 5 small gables there must be over 20 different roof
surfaces and correspondingly just as many intersections though the total surface area
might be no more than an average family house (actually perhaps 50% more considering there
are also some vertically-hung sections).

It looks to be in good shape generally and was overhauled - indeed some of it was
possibly new - in 1980. What is a reasonable average life span for a well built slate
roof? Will it always be the junctions/valleys between sections that present the greatest
maintenance/repair problem or are the surfaces just as prone?

In general, is a complicated roof structure always going to be a potential maintenance
nightmare when compared to a straightforward 'V' shape typical of most terraced houses.

Would appreciate some feedback on this.