I'd run at least 500 miles before changing to synthetic ^^, it's best to break in the engine with conventional oil.
Mobil 1 is great, I use mobil 1 extended performance (good up to 15k miles) and the 15k mile filter on my vehicles, always drains looking goldish, not black. Been running it like this in my wife's car for over 50k miles, I used to use regular M1 and change at 5k. I do usually change it around 8-10k miles, I don't like going the 15k miles, that's too long. The oil may not break down but it still gets contaminants in it. I also buy the oil and filter when it's on sale at autozone for like $35, that get's me 1 to 2 oil changes a year for $35.
Breathing in and out is good enough for me.