You should not go much beyond the recommended distance. If the belt fails the engine will be very seriously damaged - maybe needing to be replaced. A good mechanic when doing the belt change will inspect the water pump (as well as belt tensioner and pulleys) and replace it if it shows clear evidence of leakage or bearing failure. Some owners are replacing their water pumps at the 2nd timing belt change (140K miles). Only a few posts on this site have reported water pump or timing belt failures but they can happen.

If you are handy at all you can remove the upper timing belt cover and inspect the belt yourself for wear, glazing, cracks, missing teeth, contamination by oil, etc. If any of these are seen replacing the belt would be urgent.