I just returned to the office from an absolutely scintillating afternoon seminar detailing all the new postal rules and regulations. I found it very informative. You see, with all the automation the postal service is using these days, they are working to get letter and package sizes standardized.
So the lady conducting the seminar cautioned us to make sure our packages aren't too rigid. I was surprised to learn that rigidity is apparently a bad thing. But then you don't want them too flimsy either. They can be thick, but not too thick, but you don't want them especially thin. Long-sided packages are definitely better that shorter ones. Fail to abide by these rules and you will be penalized. The best advice? Use the service less, but try to stuff as much as you can neatly in each envelope. The price for extra ounces has actually gone down.