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' 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.
"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 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."
Defining moments
However, he is renowned for being a hard taskmaster on the training ground.
"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.