One classical division inside the category of positive commandments has shaped Jewish religious life more than almost any other: the distinction between mitzvot that are time-bound, tied to a particular hour, day or season, and those that are not.
The Mishnah states that women are exempted from positive time-bound commandments (Kiddushin 1:7), while remaining fully obligated in negative commandments and in most positive ones that are not time-bound. The usual examples are sukkah, lulav, shofar and tefillin; a woman is not obligated in these, though halakhic sources differ on whether she may perform them voluntarily, and on whether a blessing may be recited over a mitzvah one is not commanded to do.
The rule's rationale has been debated for centuries rather than simply applied. Medieval commentators, including the Tosafists, proposed that the exemption tracks the practical demands of running a household and raising children, obligations that recur on their own schedule; modern historians and some halakhic authorities note that the biblical text supplies no stated reason, and that the category developed unevenly, since the Passover seder and the Megillah reading on Purim are time-bound and yet women remain obligated in them.
Contemporary non-Orthodox and some Modern Orthodox communities have revisited the exemption, arguing that an exemption is not a prohibition, and increasing numbers of women have taken on tefillin, tallit and public Torah reading voluntarily, a development some Orthodox authorities accept as permitted and others resist as a departure from received practice.