For me, I consider my MS to be mild right now because I only have minor lasting effects from prior attacks. For instance, I feel some pain and numbness when anything very hot or very cold hits the lower half of the right side of my body. I also can have some fatigue, slight sensory problems, and brief periods of mild vertigo. I have had MS for about 14 years now (diagnosed at age 19), and in the past have had a small number of major attacks with coordination problems, vertigo, partial paralysis of my writing hand, and migraine headaches. So I guess I would still call my MS mild because I have only very little disability and have not had that many attacks (probably 10 or less). I don't know if that is the technical way to describe my MS, but it is how I describe it :-)