That's an excellent and practical question. There isn't a single magic number, as the ideal quantity depends on several key factors specific to your block. A good starting point is one bin at each corner of a standard residential block. For commercial or high-foot-traffic areas, you might need bins spaced every 50-100 feet along sidewalks, near transit stops, and outside popular shops.
Think about these elements: High pedestrian traffic demands more frequent placement to prevent littering. Local regulations often have guidelines, so check with your municipal sanitation department. Consider bin capacity and collection frequency—larger or more frequently emptied bins can sometimes reduce the total number needed. The goal is to make disposal convenient enough that people use the bins, not the ground. Ultimately, it's about balance: enough bins to maintain cleanliness without cluttering the public right-of-way. Observing litter patterns is the best real-world test; if you see trash accumulating between bins, it's a sign more are needed.