Do we poskin that it is a Torah mitzvah in the actual making of a sukkah, or can I just be yotzay sitting in my neighbor’s for seven days?
Answer:
There is no obligation to build your own Succah, and you can fulfill the mitzvah by living in the neighbor’s Sukkah for the duration of Sukkos.
Although the Yerushalmi, which is quoted by Tosafos, writes that there is a mitzvah in building a Sukkah (for purposes of reciting the berachah), there is no obligation to build a Sukkah if one has an option of being with a neighbor.
