Hello, Doctor. I bought super system retreat one and the advance kit. Yesterday I treated a completely calcified tooth 37; the advance kit 10 0.7 file was truly excellent. Any other file would definitely have fractured. What I really want to ask is how many times I can use these files. Because I do not have a microscope, I generally discard them after 5 uses.

10 04 is very thin; you can discard it if you feel it is being strained. 10 07 can be used more. There is not even any need to count the uses of the 17 and 25 files; they can be used multiple times.
Retreat one: a maximum of 3 molars. These numbers can vary from person to person and case to case. Some dentists put more strain on files by using an incorrect protocol, and in some canals the file can be excessively stressed. For this reason, these numbers are only a generalisation.