Distinguish maintenance, repair and restoration

Not every intervention has the same purpose.

• maintenance preserves operation and reduces foreseeable wear;
• repair corrects a fault or defect;
• restoration aims to recover cosmetic, functional or historical characteristics and may involve decisions about originality.

The distinction matters especially with older gear. Careful cleaning may be maintenance; refinishing, replacing original components or reconstructing missing parts can change the item's material history.

Before acting, ask not only “will it work better?” but also “what am I changing, and will it be reversible or documentable?”.