Q. If someone builds the Suka weeks before Yom Tov, should he also place the decoration early?
A. Although it is usually recommended to start all mitzvos as early as possible (Zerizim Makdimin), Kovetz Halachos maintains that it is better to place the decorations closer to Sukos so they will look fresh and clean.
Horav Shlomo Miller's Shlit'a opinion is similar.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a