Why does my Kia Ceed's fuel efficiency decrease after using it for some time?

I have a Kia Ceed and I've noticed that after a few months of use, its fuel efficiency has decreased significantly. I'm not sure what might be causing this issue. Can anyone offer some advice on how to improve my car's fuel efficiency?

It's possible that regular maintenance is needed to keep your car's fuel efficiency at its optimal level. Make sure to follow the recommended schedule for oil changes and bring your car in for service if any warning lights come on.

Another factor that could be affecting your car's fuel efficiency is your driving habits. Avoid aggressive acceleration and braking, and try to maintain a steady speed on the road.

Additionally, check your tire pressure regularly. Under-inflated tires can increase fuel consumption. Make sure to inflate them to the recommended level as stated in your car's manual.