I was told that the first oil change should be done at 1000 miles, but then again, the dealer also told me I dont have to do it at 1000, I should wait till 3000.....So which is it?

There is no 'right' answer, it's a matter of personal preference. I did my first oil change at 1200 miles, the next will be at 3000, and every 3000 thereafter.

yet Mazda recommends 7500 mile and warranty's the engine for 4 years. Don't think they would do that if they didn't think the oil would hold up. Having said that I will probably change at 3000 miles but do think we overdue oil changes for the most part on new cars but I guess it's cheap insurance.

Cheap insurance, and I drive my vehicle a lot harder than most people.

Mazda's recommended B service interval is 5000 miles. Did first change of oil and filter in my home garage in less than 1/2 hour at 2500 miles. Dealer at 5000 - home change at 7500 - and so on. Cost of extra oil change is $6 for filter and $6 for oil - number of extra oil change in first 100000 miles is 20 - extra total $240. Very cheap insurance for a car my wife is concerning burying me in.
John

PS At wheel pointing straight down not skyward according to SWMBO (British for She Who Must Be Obeyed)

I always thought you should only change the oil when the

warning light comes on in the dash. Done 2700 miles still no light !
By the way will the 1quart bottle be enough for the oil change ?

i did my first oil change at 1000 miles and after that i change it every 3000 miles

I am still confused on how ZoomBlack is using my board name
ZoomBlack?

Who is this other zoomblack ? . Why does he go by my user name ?

every 5k for me, on mazda's dime.

I just did my own first change at 988 miles. I will do my own change at 3750 and then take it to the dealer for the 7500. Then it's alternate DIY and Dealer every 3750 miles.