That's a great and very practical question for anyone living near the ocean. The short answer is: you should expect to replace a standard outdoor trash can in a coastal area every 1 to 3 years, compared to 5+ years inland. The harsh coastal environment is the main culprit.
The constant exposure to salty air and mist accelerates corrosion on metal components like hinges, lids, and wheels. Even "rust-resistant" coatings can fail quickly. For plastic bins, intense UV radiation from the sun makes the material brittle, causing it to crack and fade much faster. Strong, sandy winds also contribute to wear and tear.
To extend the lifespan, look for cans made from marine-grade polymers or coated galvanized steel. Choose dark, UV-inhibited colors and ensure tight-sealing lids. Placing the bin in a shaded, somewhat sheltered spot can add months of life. Ultimately, frequent replacement is a trade-off for living in beautiful coastal areas, but investing in the right materials can stretch your time between buys.