For an artist, saying no to anything but the art is strength training for the muscle required to say yes to work, yes to creation.
At Medium, Kevin Ashton tells a story of saying no: “A Hungarian psychology professor once wrote to famous creators asking them to be interviewed for a book he was writing…The professor contacted 275 creative people. A third of them said ‘no.’ Their reason was lack of time. A third said nothing. We can assume their reason for not even saying ‘no’ was also lack of time and possibly lack of a secretary.”
Get busy. Say no.