The great No 8, who retired his beloved All Blacks jersey in 1997 after a decade as an automatic selection, is now less than two months short of his 35th birthday, which will also mark the second anniversary of his arrival as Harlequins' player-coach.
But although he is wrestling with several issues - how to balance the dual responsibilities of playing and coaching for a notoriously underachieving club, how the northern hemisphere game should really be run - he is adamant that if he had his time again he would change nothing on a personal basis.
"I made the decision in 1996 to retire from international rugby within a year after the All Blacks won in South Africa. Winning a Test series in South Africa was my last ambition. I never regretted my decision but during the World Cup just gone I felt I could have been out there doing a job."
New Zealand certainly missed his strength and authority when they were overwhelmed by France in that thrilling semi-final at Twickenham, but Brooke said: "The feeling passed. I'm enjoying playing still, but it's hard to be both player and coach. After a week of coaching, I'm running out to do my best on the pitch."
Which is where the irritations start. Quins' 22-19 defeat at home by Treviso in the European Cup after leading 19-3 last weekend confounded Brooke, especially after his delight with their 32-32 draw in Cardiff in the previous game.
"You just can't afford to lose from that position," he said. "We lack the ruthlessness of great sides who would put 50 points on the board from there. It was frustrating to say the least. Ultimately, you've got to fight harder than the opposition. Sometimes if you get a good result, as we did in Cardiff, you become over-confident and that can backfire."
It is not frustration, though, which is persuading Brooke finally to give up playing at the end of the season. "In all honesty you shouldn't announce your retirement in advance, but this is my last year of playing. I just think it's the right time. I'd like to leave something at the club if they would like me to, so I'll be speaking to them about the possibility of coaching.
"It's important for the club's future that a proper youth structure is put in place so that we've got players coming through into the senior ranks. Even though that might cost money over a three-to-five-year period, it would save in the long run compared with spending millions on seasoned players."
Not surprisingly, Brooke feels the English game continues to lag behind the southern hemisphere. "There's still a gap in playing standards. The French can turn it on occasionally, as they proved against the All Blacks in the World Cup, but they can't do it consistently. It's good that English clubs are back in the European Cup and the games are on TV, but it's still different in New Zealand or South Africa, where rugby is as popular as soccer is here.
"In the southern hemisphere every competition is a stepping stone, but here the fixtures are a mess. It's 10 and a half months of chaos in which we chop and change from competition to competition.
"Not only would the players be better focused on doing one thing at a time, but also the public would have a clearer idea of what's going on.
"Internationally, I fear the game may have gone backwards over the last two years. Everyone is now obsessed with defence - it's all about having a good front row, someone to catch the ball at line-outs and kick-offs, with the rest either loose forwards or backs ranged across the pitch.
"I sometimes wonder whether the game should think about becoming semi- professional. At the moment there's not enough balance between normal life and rugby. At Harlequins, we give the players Wednesdays off either to go and earn some money in a part-time job or to continue their studies.
"Quite apart from anything else, we want them to be fresh and enthusiastic; not arriving for a match feeling tired. At training I'm constantly trying to gee them up. If all they think about or live for 24 hours a day is rugby, it's bound to seem monotonous. That's bound to affect the way they play."
The former Auckland captain, who worked as a plumber, gas-fitter and property manager in New Zealand, is now back at his day job, focusing on today's Allied Dunbar Premiership visit to Newcastle after a midweek session helping Cambridge prepare for Tuesday's Varsity Match.
Once again, Will Carling, Brooke's choice as captain, is posing problems. "Will's had a niggling calf problem for most of the season, but we've got to put pressure on him to front up. It will be a difficult game, but both teams have to win as it's a big opportunity for three precious points."
The result is vital to both clubs, but overall Brooke points to a higher purpose. "The key to the future here is who has the players under contract. In New Zealand, the union controls the players, not the clubs. If the clubs are paying the players more than England are, why would they want to play harder for England than for their clubs?"