The retirement watch on Chief Justice Rehnquist grows.

He is now in his 17th year as chief justice, and the 31st as a member of the court. Recent health problems, the political calendar, and Rehnquist's success in advancing a conservative agenda all have helped fuel the retirement speculation.

''He is the most likely to retire, and the stars are aligned right for it,'' suggested Roger Pilon, vice president of legal affairs at the Cato Institute, a libertarian legal advocacy group. Given that the Congress and presidency are both controlled by Republicans, Pilon said, ''it's the opportune time for him to retire; all that could change with the next election.''