For most of my adult life, I assumed that Jesus healed Peter's mother-in-law only once, until one day it occurred to me that some of the details do not match. Consider: although the details of the actual healing are slightly different in the three accounts, they could be harmonized to come out with a single episode; it is the context that differs. Mark and Luke have the same context; the healing they record took place not long after the ministry in Samaria (John chapter four), but certainly before the ‘Sermon on the Mount’ recorded by Matthew. The context for the healing in Matthew is quite different, and happened after that ‘Sermon’. As recorded by Matthew, Mark and Luke, I would say that the events occurring between the two healings occupy the following stretches of Text: Matthew 4:23–8:13, Mark 1:32-45 and Luke 4:40–5:15. I see a practical application to this: just because God heals you one time does not mean that you will never get sick again (even with the same problem).