The hem on the trousers should fall just to the backs of the heels and break just over the tops of the shoes. The jacket should fasten easily and fit comfortably, not pulling across the back. The hem of the jacket should reach the middle of the groom's fingers. If he goes with a vest, the buttons should fall nicely in line with the front of the jacket. The bottom should fall slightly over the waistband of the pants.
Most vests are adjustable by a slide strap in the back.
When you take your jacket off, you don't have to worry about sporting that strap or the back of your shirt. After the groom decides which shop to rent from, make appointments for the groomsmen and fathers to get fitted, about two months before the wedding. All groomsmen should get their formalwear from the same store to make sure the styles and colors are the same. Many national chains will take measurements at any store as long as the tuxes will be rented from one of the chains. Groomsmen should not guess or fill in their own measurements.