Embrace the double vent. Photograph by Chad Springer  There are
a number of questions that your tailor will ask you and, for the
vast majority of them, there is no right answer. Not so when it
comes to vents, the slit or slits up the back of your jacket.
Spare yourself a lot of grief and tell your suit maker that you
want deep double vents. You'll have an easier time sitting down
since you won't be sitting on the back of your coat. The suit
will hold your silhouette when you walk because it will give way
to your legs as they move. Vents are, quite simply, not the
place to take risks.