@Italia-Linea & guruji, really nice points...@Italia, as per my experiance i'll say if you are driving in city with heavy bumper to bumper traffic change your oil with the help of visual inspection. As soon as you'll find out your engine oil is black & smells pretty much like brunt carbon change it! In my case my oil was looking totally black like tar at only 6500kms. Our driving conditions matter a lot! As our cars are diesel cars its normal that oil mostly looks black in color(guys correct me if m wrong) but if it smells like burned then you better change oil & filter.