tadir v'sheino tadir (daf yomi)

The following isn't my own heara, but it is a good one: The gemara says that the shir shel shabbos (accompanying the mussaf) is more tadir than the shir shel rosh chodesh. If you look at Gemara R"H 31a and Rambam Temidin U'Musafin 6:9 you will not that the shir shel shabbos is divided into "haziv lach" of parshas Ha'azinu, and one section is read each shabbos. It comes out that any particular part of the shir shel shabbos is only read once every six weeks - less frequently than the shir shel Rosh Chodesh. Obviously, the tedirus is determined based on the general chiyuv and not the specific action. See Turei Even Megilah 29b who says we read the shabbos laining before the Rosh Chodesh laining because the chiyuv kerias hatorah for shabbos is more tadir, even though the particular parsha that we are reading only gets read once per year.