If you notice dark, gritty oil on the dipstick or a burnt smell

https://spark-wiki.win/index.php/The_Ultimate_Synthetic_Oil_Change_Guide_for_Greensboro_Drivers

If you notice dark, gritty oil on the dipstick or a burnt smell, it might be time for an oil change sooner than scheduled; contaminants and heat degrade oil faster under severe conditions.