Warping, Sagging, or Poor Installation
If your home has any roof-to-wall intersections, check if the shingles or the wall show indications of moisture intrusion or an improper installation. There should be flashing hidden underneath the shingles and the wall to stop water leakage. But if you notice leaking, warping, or sagging---the flashing may be damaged.
Taking care of this now can prevent bigger headaches later!