It has been a long time since I delved into any philosophy, so I am just dipping my toes into the Ship of Theseus as I have not encountered this mind puzzle before and just looked it up. It is an interesting question. I almost immediately began thinking in terms of the human body on a cellular level. Physically our cells make us who we are. They die and are replaced by new cells constantly. So if millions of cells are replaced in a year's time, would an individual be the same person from the one the year before?
"The price of freedom is eternal vigilance."--Thomas Jefferson