Oil Change - Non Synthetic

[NickCats]

Question for you guys - my Benz is due for an oil change. I usually change the oil every 3k miles, but the last time I had the car in for service they told me "You know, you can wait and change the oil every 4,500 miles, even though the car runs non-synthetic. New oils are so much better that you don't have to change it every 3,000".

( Keep in mind this is from the idiot that quoted me $800 to replace the transmission flex plate and handed me a bill for $2200 ! )

I'm bringing my car in to my regular shop next weekend. Should I continue with the 3k mi interval or wait until 4.5k ?

( Keep in mind this is a 1998 with 130k miles )

Thanks,

Nick