When you read the historical accounts it is often quite surprising to read how many accused witches didn't confess. Only in certain regions where a full scale panic took place and anyone was susceptible to being accused and with no limits on torture were there close to 100% convictions after confession. In a more normal situation torture had its limits. Usually 3 applications was the maximum. A good example being in a region of Switzerland where out of 79 women accused and tortured, 51 held out and had to be acquitted. As to how much a human being could endure in the most extreme of situations the best example probably is of Marie Holl, also of Nordlingen, who went through an amazing 56 sessions of torture before being allowed to go home.