I was reading "Time scales in the context of general relativity" Bernard Guinot, and a few other papers whose names I forget, and was surprised that there was apparently some desire by some physicists to give coordinates units. It seems that the current recommended practice is that coordinates don't have units (which is the position I take), but I fail to understand why this is not unanimously accepted, nor why one would want to assign units to coordinates, such as the above mentioned "TCB seconds". A change in the T coordinate depends on which coordinate system you use, and not to anything actually measurable. Not being a physical quantity in and of itself, it seems to me to be wrong and confusing to assign a unit to a change in coordinate. Any comments?