oil change, oil question
 

Okay I recently purchased a 2008 escape, V6 with the Duratech engine. I've been reading the owners info booklet and I am not seeing where it states what mileage to change the oil. I'm sure it's an over sight on my part. Would somebody answer this blind mans question re: when to change motor oil?
second question is I've heard synthetic oil is the way to go. Is it as good as they say it is and does it have to written that it is okay to use synthetic oil in order to not void the warranty?
Thanks in advance. I will have questions for you guys as I'm not a "car brainiac.."