How do you know when to change a op-ti spark?

You should consider changing an op-ti spark when you notice signs of poor engine performance, such as rough idling, decreased fuel efficiency, or difficulty starting the engine. Additionally, if you see physical wear or damage to the spark plug electrodes or if they are due for replacement based on the manufacturer's recommended maintenance schedule, it’s time to change them. Regularly inspecting the spark plugs during routine maintenance can also help determine their condition.