I have these for occasional electrical work with my brother-in-law and for general use during the winter.  I have used it several times now in cold weather and kneeling in the snow.  So far they have been exceptional!  They are very warm when wearing a pair of pants under these and then a coat with it as well.  I have not felt the cold on my legs or core when wearing these bibs so far.  They fit very comfortably.  Other users have mentioned how to determine the sizing so I will not go into great detail over that, but I normally wear a 32" waist and got a 34" in waist for the bibs and they fit well/almost snug when wearing a normal pair of pants under them.  Also I have the 32" length as that is my normal length in pants and they fit just fine without dragging on the ground at all.  Overall they are warm (as I have used with a windchill in the single digits already), they are comfortable & flexible while still being very sturdy and should be very durable for years to come!  Great purchase for outside winter workers and those of us who want a good warm pair of bibs that we may never have to replace!