check your hoses
I just had a wake-up call, telling me to check the hoses in the engine compartment for possible wear, rubbing against each other and against other objects.
I had a new mechanic do my yearly service this week, and he found two hoses that were worn to the point where they had to be replaced, and an a hole in the forming stages in the oil pan where one of the now replaced hoses was rubbing. These wear points should have been found and corrected by the (different) mechanic last year.
My mechanic this year checked every hose, and used nylon ties to prevent them from rubbing in the future. I feel very lucky to have changed mechanics and not had an engine oil or power steering oil leak while on the road.