To be sure, none of the sitting justices has given any indication they are preparing to retire and all appear to be in good health.
Still, speculation has swirled around Justice Ruth Bader Ginsburg, 77, who, as one of the court's oldest justices, endured colon cancer in 1999 and battled pancreatic cancer last year. As a member of the court's liberal wing, she would presumably want to vacate her seat during a Democratic administration.
Ginsburg has emphatically denied that she has any intention of stepping down, and sources say she is determined to continue to serve.
"She looks frail; that's always been true, and it has always caused people to underestimate her," wrote Tom Goldstein on ScotusBlog.com. "But she is at the top of her game and has no reason to retire."
Nonetheless, if Ginsburg or another justice should step down by choice or for health reasons in the years ahead, look for Obama to revisit some of the same names on his most recent list, sources say.
"If Obama faces a tougher Senate after the midterms and wants an easier go the next time around, he could well pick Garland," Rosen said, referring to the judicial moderate.
On the other hand, said the Brookings Institution's Stuart Taylor, "there will be huge pressure for a replacement to be a woman" or other minority to further diversify the court.
"In any event, I don't think they [the administration] will have to start from scratch," he said.
But the wild card in a potential future Obama nomination is the prevailing political landscape and the youthfulness of previously vetted potential nominees. As the clock ticks, possible picks like Garland and Wood will only continue to age.
"Unless it's next year, they'll all be a year older, and in three or four years, they may be deemed too old," said Taylor of some of Obama's short-listers who are approaching 60.
"Once you get to be 60, 62 or older, forget about it. Cross them off the list," he said.
ABC News' Ariane de Vogue contributed to this report.