That's an excellent question that gets to the heart of practical urban management. The replacement frequency for a heavily used public trash bin isn't a single number, as it depends on several key factors. Generally, in high-traffic urban areas, you can expect a well-made stainless steel or heavy-duty plastic bin to last between 3 to 7 years before needing replacement. However, bins in extremely heavy-use locations, like outside a busy train station or in a popular food court, might require replacement every 1-3 years.
The lifespan is primarily determined by the material's durability against constant use, weather exposure, and unfortunately, vandalism. Modern, robust designs are built to withstand a lot of punishment. The maintenance schedule also plays a huge role. A bin that is regularly cleaned, serviced, and has minor repairs (like fixing a hinge or latch) will last significantly longer than one that is neglected. Ultimately, a proactive replacement strategy is more cost-effective for cities than frequent emergency repairs. It's less about a strict timeline and more about consistent monitoring for signs of irreparable damage, rust, or structural failure that compromises its function or safety.