Question about The Ultimates.
Is each Vol. a single year long story arc or is it in the standard format? ( Mini acrs/stand alones ect.)
Each volume is split in two parts, although some elements from the first part carry over into the second and the last issue of the first half tends to be a something of a cliffhanger leading into the second half.
It's not quite a year-long arc - each "half" does make sense on its own, but what happens in the first half does impact what happens in the second. You might as well read them in order. That way it'll make the most sense.