fits and starts, by

In bursts of activity, spasmodically. The fits portion of this expression dates from the sixteenth century, and the pairing with starts came soon afterward, in the early seventeenth century. “Thou hast these things only by fits and starts,” wrote Robert Sanderson in one of his Sermons (1620). John Ray’s proverb collection of 1670 put it slightly differently: “By fits and girds, as an ague takes a goose.”