This is precautionary work. Asphalt shingle roofs typically last 20–30 years depending on climate, ventilation, and installation quality. At 15–20 years, an inspection makes sense to understand remaining life and catch small issues before they become expensive.
The previous chimney flashing repair suggests that area may warrant extra attention. If that repair is holding well after 5 years, good sign. If showing wear, may indicate broader flashing concerns.
Inspection outcome will determine whether this becomes a minor maintenance item or a major capital expense. Worth scheduling before rainy season to address any issues found.