I've written many many pages with these. They always write and the fine line
allows writing very small comments. I buy them by the box because I don't want
to run out. The ink seems to last a long time.
I love using this pen. I carry it in my pants pocket. They are a bit fragile. I
have broken two in the threaded part of the upper barrel. I fixed them with a
tiny dot of super glue. I just use red, blue and black. Very handy and a fine
line on various qualities of paper.