always side vents

i prefer not to deal in absolutes, but here is one that is indeed always true.  the three options you have are no vent, center vent, or side vents.  besides being the most contemporary look, side vents have more upside with regard to function.  with your hands in your pockets, your jacket lays flat. when you sit down, it doesn't bunch up and wrinkle.  so if any part of your day includes putting your hands in your pockets or sitting down, always tell your tailor you want side vents.