That's an excellent and very practical question. As someone who's specified and maintained street furniture, I can tell you the finish is arguably the most critical component for long-term appearance and cost-efficiency. Modern metal public waste bins don't just use ordinary paint; they typically employ a multi-layer defense system.
The gold standard is a thermosetting powder coating, applied electrostatically and then cured with heat. This creates a remarkably hard, uniform shell that is inherently more scratch-resistant than liquid paint. For high-vandalism areas, bins often feature an additional anti-graffiti topcoat. This is usually a polyurethane or fluoropolymer clear coat that creates a non-porous, sacrificial barrier.
Against scratches from everyday use—like being bumped by bikes or scraped by debris—a quality powder coat holds up very well. It might show fine scuffs over years, but it rarely chips down to the metal, which prevents rust. Deep, intentional gouges with metal objects can penetrate the finish, but the toughness makes this difficult.
For graffiti, the anti-graffiti coating is the hero. Most spray paint and markers cannot chemically bond to its slick surface. Instead, the graffiti sits on top. Maintenance crews can then remove it using specific mild solvents or even pressure washing, without damaging the underlying finish. Some advanced systems are "permanent," where graffiti wipes off repeatedly, while others are "sacrificial," where the topcoat itself is removed and reapplied after severe attacks.
So, while no finish is utterly indestructible, the technology has advanced tremendously. A well-made bin with these finishes can look good for a decade or more with proper cleaning, surviving both accidental scratches and deliberate graffiti far better than the painted steel bins of the past. The key is specifying the right finish tier for the expected location's vandalism risk.