Most hairline cracks are not serious. If the structure has been previously painted, the cracks are usually in the material that was used during painting and not in the stucco. This has been true in most of the cases that we have seen. We can match an addition to your home. The only variable is the age of stucco.
Stucco becomes dirty and oxidizes as it ages.
The best way is to avoid this is to first complete all of your remodeling work and then stucco coat everything, if possible. Cement stucco is basically cement exterior plaster and has been in use for over 8000 years. Most older homes have cement stucco applied on them. EIFS or dryvit product has been around in the US for approximately 30 years. It is a thin synthetic skin over styrofoam.