Not only is "The Measure of a Man" an exemplary episode of Star Trek: The Next Generation, it is also the episode that confirms Data's status as an individual.

Source: https://screenrant.com/data-human-star-trek-tng-before-picard/

Part of the justification for Data's death in was the idea that Spiner didn't feel he could continue playing an ageless character any longer.

Source: https://screenrant.com/star-trek-data-aging-tng-retcon-forgotten/

The chip was also meant to fill in Data's missing memories, allowing him to recall life on the colony prior to the Crystalline Entity attack.

Source: https://www.slashfilm.com/1329793/who-created-data-star-trek/