During the 20 past years, the management of multiple sclerosis (MS) has largely changed especially concerning therapeutical approach. Before 1996, treatments were restricted to corticosteroids for relapses, several symptomatic treatments and unselective immunosuppressive drugs (azathioprine, cyclophosphamide, methotrexate) with a low evidence of any efficacy. In the present review, we analyze the principal real-life cohorts of MS during several periods (before therapeutical modern area, first-generation treatment area and most recent period). Despite many methodological problems, we observe globally a delay of around 3–5 years between untreated cohorts and first-generation treatments for going to EDSS 6 which is probably the most robust score. This delay is clearly increase to at least 15 years with the most recent cohort treated first and second-line treatments confirming that early and more intensive treatment are necessary to have a long-term efficacy on disability progression and especially on severe disability represent by EDSS 6. Larger cohorts with longer follow-up is necessary to confirm these tendencies and OFSEP observatory or MS base will probably provide us the possibility to conclude in a couple of years.