The tile roof underlayment (90#) cracks with age
Often, leaves and other debris are found under the tile if the roof is not kept clean.
This aids the deterioration process because moisture is constantly laying on the roofing surface.
As shown in the image above, The membrane holding the shingle together becomes weak and the shingles are susceptible to blow offs.
In this picture, a high wind took off a section of the roofing, exposing the plywood and allowing rain to damage the unit. Other shingle roofs in this apartment complex with new roofs were unaffected.