I was sure that Brent Spiner said he wouldn't reprise his role as Data, after Nemesis...and digging around I found this answer to a question 10 years ago, that quotes an interview:
when Spiner was asked if he thought Data could come back he said:
I don’t think that could happen. Look at me. I am a shockingly older gentleman. I don’t see that I could wear that makeup anymore. I think that would look really stupid. I love the character and I wish I started it much younger, but I was already in my mid sixties when I started [joke]. I just don’t think I could get away with it. Yeah they could CGI it, but why not just CGI the whole character and forget about me.
So what convinced him to come back, and not just let the producers 'CGI the whole character'?