That's a great question, and one that anyone buying an outdoor bin should consider. The short answer is: it depends heavily on the quality of the plastic. Direct sunlight is one of the biggest challenges for plastic outdoor items.
High-quality trash cans made from resins like polyethylene (HDPE or LLDPE) are often treated with UV inhibitors or stabilizers. These additives are crucial. They act like sunscreen for the plastic, slowing down the degradation process caused by the sun's ultraviolet rays. A can with good UV resistance can last for many years in the sun without becoming overly brittle or losing its color dramatically.
However, cheaper, thin plastic bins without UV protection will deteriorate much faster. You'll notice the signs: the color will fade and become chalky, the plastic itself may become brittle and crack easily, especially in colder weather, and it might warp or become misshapen. The constant heating and cooling cycle weakens the material over time.
To maximize longevity, look for cans labeled "UV-resistant" or "weatherproof." Darker colors like black or forest green tend to fade less noticeably than bright reds or blues. Placing the can in a slightly shaded area, if possible, can add years to its life. Regular cleaning also helps prevent grime from baking into the surface.
So, while no plastic is completely immune to sun damage, investing in a well-made, UV-protected trash can makes a huge difference. It can hold up very well for its expected lifespan with proper care.