"It was always going to come to an end at some point (and)... part of (retiring) scares you a little bit," he told the New Zealand Herald yesterday.
"I've done the same thing for so many years, so all of a sudden to be having to figure out something else to do is a bit daunting."
The 34-year-old has not yet said he will retire at the end of the Rugby World Cup in England from September 18-October 31.
The signs, however, are that he will call time on a career that has earned him three World Player of the Year awards and set the record for caps (142) and most tests as captain (106).
McCaw got a standing ovation when he was substituted during New Zealand's 41-13 win over Australia at Auckland's Eden Park on Saturday night.
The reception was a rarity amongst the traditionally stoic New Zealand crowds, whose normal manifestations of feverish excitement amount to an "All Blacks! All Blacks! All Blacks!" chant for a few seconds during games.
Part of that reaction could be related to the fact McCaw was one of six stalwarts who have likely played their last test in New Zealand after being part of an All Blacks side that have dominated world rugby in the past decade.
Conrad Smith, Ma'a Nonu and Dan Carter have all committed to lucrative club contracts in France following the World Cup, while Tony Woodcock and Keven Mealamu, like McCaw, are expected to retire.
The reason for choosing to wait on confirming the decision, McCaw, like Mealamu, has said, was because he did not want to close off his options.
"I haven't shut the door totally because I wasn't sure how I'd feel come the end of October. I really wanted to make sure I didn't get caught up in the 'It's your last game here, last game there' stuff.
"The door is open a little bit but I just want to concentrate on what I'm doing now and get a bit of separation after the World Cup.
"There's no doubt when you start having to watch a few games, I'll miss it like hell".
