Marriage with cousins is permissible, it has been explicitly permitted in 33:50.
Nothing authentic has been narrated from the Prophet ﷺ regarding whether it is encouraged or discouraged. Nor has anything been narrated regarding doing it over several generations.
Some scholars among the Shafi'is and Hanbalis have adopted the stance that it is preferable that the bride should not be among the close relatives (such as cousins) because there is a risk of divorce and hence may become a cause of severing ties of kinship (see المغني) and they also base it on the hadith (of doubtful authenticity):
لا تنكحوا القرابة القريبة فإن الولد يخلق ضاويا
Don't marry a near relative as in that case a child is born weak
Others have denied this because the Prophet ﷺ himself married his cousin Zaynab bint Jahsh, and he married his daughter Zainab to her cousin Abu al-As ibn al-Rabi', and he married his daughter Fatimah to his own cousin Ali ibn Abi Talib.