That's an excellent question I get from homeowners and property managers all the time. Having used both types for years, I can give you a practical, real-world comparison.
Let's be honest: metal bins, typically galvanized steel, have that classic "heavy-duty" reputation for a reason. They feel substantial and can handle rough handling in commercial settings. However, their main enemy is rust. Even galvanized coatings can chip, and once rust starts at a seam or scratch, it spreads. In coastal or high-humidity areas, this deterioration accelerates. They also dent permanently from impacts.
Modern plastic bins, made from high-density polyethylene (HDPE) or similar resins, are surprisingly tough. They won't rust or corrode, which is a huge win. They flex on impact rather than dent, often bouncing back from minor bumps. The UV inhibitors in quality models prevent significant fading and brittleness for many years. Their weakness is extreme temperature swings; very cold weather can make them slightly more prone to cracking if hit with extreme force, and prolonged, direct intense heat can cause warping.
For most residential settings, a good-quality plastic bin is perfectly durable and often lasts 7-10 years or more with minimal care. It's lighter, quieter, and requires no maintenance. For high-traffic commercial areas where bins might be mechanically lifted or suffer severe abuse, a heavy-duty metal can might still be preferred, accepting the need for eventual rust treatment or replacement.
So, durability isn't a simple "metal wins." It's about the *type* of wear. Plastic excels against weather and corrosion; heavy-gauge metal excels against brute mechanical force. For 90% of homeowners, a thick, UV-protected plastic bin offers fantastic, worry-free durability.