Life expectancy is often misunderstood and similarly often incorrectly represented. The 'official' quote once was 1-3 years for bulbar onset and 3-5 years for limb onset, now they more often say 2-5 years without mentioning onset. Numerous studies, however, have shown typical patients have less than a fifty-fifty chance of making three years from symptom onset, even in limb onset ALS. When they mention the life expectancy numbers they are almost always talking about averaged survivals from DISEASE ONSET to death: not diagnosis. Because some patients live quite a long time they tend to draw such average up much more than those with 'fast regression' draw the average down. Since they are around longer they are more likely to be detected surveys and therefore included in new calculations, too. The mid-point of limb onset tends to be about eight months longer than the mid-point for bulbar onset yet neither produces reliable predictions (medians not means). Most scholars consider remaining life expectancy nearly impossible to predict. There are positive and negative co-factors but exceptions are found to be numerous. Patients are wise to live each day as though it would be their last. Perhaps unsurprisingly, patients who are theologically active often appear to live longer. The difficulty of predicting life expectancy is one of the most problematic components of clinical study design.