How often should I replace my Ford Mondeo's spark plugs?

I have a 2012 Ford Mondeo and I'm wondering how often I should replace my spark plugs. I've heard conflicting recommendations, so I'm not sure what to do. Can someone with experience give me some advice?

It is recommended to replace spark plugs every 30,000 to 50,000 miles, or every 5 years, whichever comes first. However, if you notice any signs of wear or poor performance, it may be necessary to replace them sooner.

I have a similar model and have found that replacing the spark plugs every 40,000 miles keeps my car running smoothly. It's always better to err on the side of caution and replace them earlier rather than risk damaging your engine.