The lifespan of solar street lights varies due to various factors, including product quality, usage environment, and the lifespan of various components. Generally speaking, the lifespan of solar street lights can be between 5 and 15 years, but the specific lifespan is affected by the following key components:

1. Solar panels: The service life of solar panels is usually longer, usually up to 20 years or more. Even though solar panels may only have a certain amount of light attenuation (about 30% or more) in 20 years, they can still be used.

2. Controller: The lifespan of a controller is generally 8 to 10 years, depending on the quality of electronic components and the usage environment.

3. Battery: In the past, solar street lights often used lead-acid colloidal batteries, which had a short service life of about 3 years. The commonly used lithium batteries now have a longer lifespan, exceeding 5 years or even reaching 10 years (discharge depth calculated at 30%), which greatly improves the overall service life of solar street lights.

4. LED light source: The service life of LED light sources is also very long, generally reaching over 50000 hours. If used for 10 hours a day, its lifespan is at least 10 years or more.

5. Lamp post: The service life of lamp posts is usually longer. If high-quality materials such as Q235 steel or hot-dip galvanizing are used and rust prevention measures are taken, the service life can reach 25 years or even longer.

In summary, the lifespan of solar street lights is a relative concept, which is influenced by the lifespan of each component as well as the overall design and maintenance quality. Under ideal conditions, the maintenance cycle of a reliable set of solar street lights should be 8 to 10 years or more, and the overall service life can reach 10 years or even longer. Regular maintenance and inspection are essential to ensure the normal operation and extend the service life of solar street lights.