change the entire kit!
i recently acquired a ford escort estate, 112,000 miles on it but immaculate condition and service history.
Before taking it on the continent I got a mate to change the cambelt kit to avoid potential problems. Apparently the cambelt had been changed not long back, but when he stripped it down, he saw that although the belt was good, cracks were starting to appear in the pulleys it went round. Could have resulted in disaster. So make sure that the entire lot is done!