It is proposed, and recommended, that vacuum chambers and systems to be built of austenitic stainless steel should be designed for the thinnest walls possible, consistent with structural integrity under atmospheric pressure. The reason for this design goal is to greatly reduce the time, effort and cost needed to outgas the chambers to reach the desired and specified vacuum level. Of course, this is directly contrary to the universally accepted concern with permeation of atmospheric hydrogen. This concern has recently been shown to be greatly exaggerated. Atmospheric permeation is at least 100 times less than previously estimated, and is possibly non-existent. Errors in the previous estimate will be briefly summarized. Published outgassing of two relatively thin-walled chambers will be discussed. Methods to predict the hydrogen outgassing rates for specific wall thicknesses and bakeout procedure will be given. Vacuum oven bakes result in a flat, uniform atomic hydrogen concentration profile within the wall and give clean, unoxidized surfaces; the instantaneous outgassing rate is directly proportional to the hydrogen recombination coefficient (at the bake temperature), and to the hydrogen concentration level, while the time required for this rate to decay varies linearly with the wall thickness. In contrast, an 'in situ' bake, with atmosphere on one side and vacuum on the opposite side of the wall, results in an asymmetric concentration profile, with a minimum on the atmospheric side and a maximum on the vacuum side. To further confuse the issue, room temperature operation also causes an asymmetric concentration profile, but in the opposite direction, with the minimum on the vacuum side. Thin walls can be stiffened with rolled in ribs which are substantially thicker than the wall itself. This ribbed structure can be further strengthened by coaxial wraps over the ribs, or by longitudinal bars added outside the ribs. Methods of measuring and calibrating the hydrogen outgassing rates, and of presenting the data, will be discussed briefly.