In general, Citizen Eco-Drive watches do not require regular battery replacements. The Eco-Drive technology utilizes a rechargeable battery that is charged by light, whether it's natural or artificial. As long as the watch receives sufficient exposure to light, it will continue to function without the need for a new battery.

However, it's worth noting that the rechargeable battery used in Eco-Drive watches has a limited lifespan. Over time, the battery's capacity to hold a charge may decrease, resulting in diminished performance. If you notice that your Eco-Drive watch is not holding a charge as well as it used to or if it stops functioning despite adequate exposure to light, it may indicate that the battery needs to be replaced.

When the rechargeable battery of an Eco-Drive watch reaches the end of its useful life, it is recommended to have it replaced by an authorized Citizen service center or a professional watch technician. They can properly handle the replacement and ensure the continued functionality of your watch.