Where ever the custom is to repeat words in the hallel you repeat and where there is no custom too, you don’t repeat. Where ever the custom is to say a bracha at the end of hallel you say the bracha and if it’s not he custom you don’t. You’re not allowed to buy an esrog in the shmeta year. So we buy a lulav and the store owner gives the esrog as a present.

Succa 3:12

Originally the lulav was taken seven days in the bais hamikdash, and out side only one day. Reb Yochanan Ben Zachai said, after the bais hamikdash was destroyed it should be taken every where all seven days as a remembrance for the chorban. He also said that chadash is prohibited to be eaten till the end of the 16^th of Nissan.