The seismographic range of institutions, causes, and charities staging sales creates a constant barrage for artists. “It’s a side business keeping up with all the auctions,” said Simmons, who gave away 16 works last year. “It takes an amazing amount of, for lack of a better word, administrative time. It’s very hard to keep it all going.” Artist Marilyn Minter said she receives requests for donations every week. Rob Pruitt fields about 20 solicitations a year.