That's an excellent question that many city planners and facility managers consider. From my experience observing urban infrastructure, both materials have distinct durability profiles.
Plastic bins, typically made from polyethylene, offer great resistance to rust and corrosion – a significant advantage in coastal areas or where de-icing salts are used. They won't dent like metal and are generally lighter. However, they can become brittle in extreme cold and may fade or become stained over time. High-quality rotational-molded plastic bins can last 5-10 years with proper care.
Metal bins, usually galvanized steel or aluminum, feel more substantial and are often preferred for high-traffic areas. They handle heavy impacts better and aren't prone to UV degradation. The downside? They can rust if the coating is damaged, they dent noticeably, and that familiar "clang" can be noisy. A well-maintained metal bin can easily last 10-15 years or more.
For true durability, consider your specific environment: plastic excels in wet climates, while metal withstands physical abuse better. Many cities now use hybrid approaches – metal frames with plastic components – to balance strengths. Ultimately, proper maintenance matters more than material alone for extending any bin's lifespan.