Which do you think is better and why? For me, I don't get why people using synthetic oil tends to change it every 10k. Is it because of the claim that you don't need to change until you hit 10k? Kasi diba, once you start/use the engine there's already wear and tear in it? Pieces of metal, dirt etc.. are inside the engine and if you're going to wait for 10k diba ang tagal pa nung mga dumi na naka deposit at patuloy na umiikot sa loob ng engine?

I'm not saying sythetics are bad, it's just that I'm having doubts about its 10k interval claim.

What do you think guys? Discuss!