However, the veteran New Zealander is working just as hard as ever -- as his new Samoa players are discovering.
"A big challenge for me is to get the Samoan team to the Olympics in four years' time."
Tietjens is quick to dismiss any suggestion he could emulate the feats of Ben Ryan, who transformed Fiji into an Olympic champion
and two-time Sevens World Series winner in a fairytale three-year stint.
Samoa didn't even qualify for Rio 2016, and finished ninth in the world series despite a notable Paris Sevens victory, beating Fiji in the final.
Tietjens' predecessor, Ryan's fellow Englishman Damian McGrath, was sacked after only one season in charge.
"I couldn't believe how small Samoa is compared to Fiji," Tietjens says. "You've got a population of 185,000 in Samoa and you've got a million people in Fiji, you know?
"What I'm trying to do is build some talent on the island. In Fiji you've got a massive amount of talent ... Samoa isn't great there -- I think we've got more Samoans in Auckland than what we have in Samoa."
However, as Ryan found in Fiji, Samoans love the game of rugby -- and it plays a big part in community life.
"Every time you drive out to the airport, you see 60-70 kids out there, always a rugby ball in the middle," Tietjens says.
"And that's awesome -- I now know what it means for these guys to represent their country."
In fact, he says, some players took it rather hard when they found out they hadn't been selected for a tournament squad.
"They were so emotional, I didn't realize it meant so much to them. One player said to me, 'I love this team.'"
Pushing the players
Tietjens ended his long reign as New Zealand coach -- which started when rugby was still an amateur sport -- after the Rio 2016 Olympics, where the team surprisingly failed to win a medal.
He had to wait for his contract to expire
before taking charge of Samoa at the start of January, but went to the 2016-17 series' opening Dubai and Cape Town tournaments as a spectator.
Samoa didn't reach the quarterfinals in either event, and Tietjens -- who turned down an offer to coach Kenya
-- began his tenure by taking the players to New Zealand to test their fitness at a high performance center.
"I've been pushing them particularly hard and, mate, they're a dream to coach," he says.
"They don't give in, they keep going. I had an amazing player who said to me, 'Coach, I'm in Samoa, I train twice a day and I eat less food and I've put on weight. I've been in NZ three weeks and I've been training twice a day, working hard and I eat more food and I've lost 7 kg.
"That says it all, really."
A time of transition
Almost inevitably, Samoa's first game at last month's Wellington Sevens was against the team with which Tietjens won a record 12 world series titles, two Sevens World Cups and four Commonwealth Games gold medals.
New Zealand won 33-7, but was beaten by Fiji in the quarterfinals of its home event, while Samoa lost all three group games.
The All Blacks Sevens are also in transition, and new Scottish coach Clark Laidlaw -- who worked under Tietjens earlier in his career -- has vowed to revamp the national sevens program
when he starts his role in June.
Tietjens admits he was unhappy with the team's preparations for Rio 2016, where New Zealand finished fifth and lost star XVs convert Sonny Bill Williams to injury early in the tournament.
"The last 18 months, I lost a lot of the enjoyment factors because our program didn't get the support I believed it deserved going into the Olympics," he says.
'Respect on the island'
Tietjens is now focused on improving Samoa's standing in the world series -- the team again failed to make the Cup quarterfinals at last weekend's Sydney Sevens -- and use next year's Commonwealth Games in Australia as a stepping stone towards Olympic qualification for Tokyo 2020.
He will not be based in Samoa full-time, so has enlisted the help of Stephen Betham, who coached Samoa to its only world series title in 2010 and took the 15-a-side national team to the 2015 World Cup in England.
"He's got respect on the island," Tietjens says of his assistant. "He's my go-to man when I'm not there, but I still will be there lots and lots of times.
"I see it as a refreshing change that the coach is not always overseeing the players. I'm getting information I need and I then move onto the island, I spend time with them, seven to 10 days before we go away to the tournament, and then I spend time with them at the tournament."
Tietjens is used to working with Pacific Islanders -- New Zealand is a common destination for many in the region, and there are more Samoans living in Auckland than in its capital Apia.
Playing rugby there is seen as an opportunity to earn a better living, and many New Zealand-born All Blacks have family roots in Samoa, Tonga and Fiji.
"The biggest challenge for me initially was getting to know all of the names of the players that I'm now working with. In New Zealand obviously I have a dialogue of a massive amount of players coming through the systems," Tietjens says.
"But I really looked forward to taking this role. I've worked with so many young Samoans coming through the NZ teams and they've been great to work with."
Tietjens is affectionately known as "Titch" -- and local newspapers dubbed him "Sir Titch"
after he was knighted for his services to rugby by Britain's Queen Elizabeth in 2013.
However, he is renowned for being a hard taskmaster on the training ground.
"He pretty much broke everybody," former All Blacks winger Eric Rush once said of Tietjens' first session with the team in 1994.
"I'm a real believer in you always stick with what works for you and, of course, still looking for new innovation moving forward," the coach says now.
"You can't be a top sevens team or a top sevens player without committing yourself to a lot of hard work. Our game is all about conditioning, and then comes decision-making at crucial times.
"Our game is ruthless. It comes down to defining moments."
Tietjens has plenty of defining career moments -- he is already a member of rugby's Hall of Fame, an honor usually reserved for after retirement.
Samoan rugby fans will be hoping he can add another.