Is the roof material having problem, the attachment method of the tiles, the underpayment that is the actual water barrier, or exposed things like rafter tails?

Tell anyone replacing rafter tails to stay the hell off the roof.

"Tell anyone replacing rafter tails to stay the hell off the roof."

Exactly. That's a job done from exterior scaffolding, not climbing about on the roof.

If correctly installed, concrete roof tiles are basically a lifetime roof. There is no real reason for them to fail. If the color that you have has been discontinued, then I'd be contacting the company about buying a couple of boxes of unsold back stock. But, I'd always recommend having "spare parts" for any type of finish on your home, from the siding to the roofing, to the brick, etc. It's not a function of the material. It's just common sense.

If the color has been discontinued long enough that there is no backstock, then I'd talk with a company representative about what would be the closest color match. There are plenty of 200 year old homes with slate or tile roofs that have patches that aren't quite the same color, and I personally think it's actually charming to see the evolution of the structure over time.

"If the color has been discontinued long enough that there is no backstock..."

Steal them from a less visible spot (like the back) and put the new ones there.

This is the longer story with details contributed by husband. What started this odyssey was the need for a paint job. But first there was rot in the rafter tails to be fixed. It is a 33 year old home with spike/ferrule gutter installation directly into the rafter tails (no fascia and no soffits). A recent rare ice storm followed by high winds introduced our house to a big fir branch that clipped one gutter. Not a big problem, but put them all together with our concrete tile roof and it is looking like a "begetter" project: rot repair -> broken roof --> new roof --> new gutter. (The last one may be necessary anyway; it wasn't installed very well.)

The heavy 17-inch long tile is mounted with a lip that simply hooks over a horizontal wood slat. The spacing between slats is such that there is about a 10-inch gap (estimate) in the middle of the tile that is unsupported. Step on it and it cracks. DH probably won't take that step, but as y'all observed repair folks won't be that careful.

I like the idea of scaffolding, but it is one of those tri-level houses with a "broken" roof line. To get to the second floor rafter tails not around the perimeter of the house, the scaffolding would have to span from front to back of the house over the top of the peaked first floor roofing. Even then, more than half of the tails would be too far below the scaffold to work on.

We sure don't want to replace the roof just to get something more walkable. Maybe we could get by without a gutter on the upper level "interior side". (Not sure about that, though.) We can safely take the gutter down, but some of those rafter tails still need repair. Maybe I can send the DH to carpentry school for that?

Anyway, I was very excited to own a home with a 50 year/lifetime concrete tile roof. No more. It is impossible to stay off the roof. Even without rot, there is upper level painting to be done and the tile grows moss even better than cedar shakes. It looks very spiffy, but think twice before installing such a roof.

Thanks for the suggestions so far and please keep them coming.

Spikes & Ferrules. Sheesh!