I know it's probably depend on each person, but i was wondering when's the best time?

One of my friends told me, I should flip it every time I get oil change.

 

Rotate every 6-8k miles is what I am.gana do.

 

Flip your tires???? As in rotate??? the fronts are smaller than the rears, so you can't rotate...

Are you meaning flip as in your tires are directional, and your going to have them dismounted and remounted on the opposite sides??

 

Yes, flipping it from left to right and right to left. I am curious "when" is the best time to flip it.

 

I think every oil change is kinda vague... some change oil at 3k, some go at 5-6k, I would say every 8-10k miles would be a safe bet.

 

If you are getting even wear on the tires there's no point in flipping it.
Only time I've ever had my tires flipped were because I was getting faster wear on the insides due to negative cambers.