The strides have been substantial. The 26-year-old remembers the importance of the pre-London period to her development.
"In the two years going into London I improved so much to get to the point I did in London," Boyle said of the Olympic meet when she made two finals.
"Since then I've made more improvements and got myself into the place where people noticed my improvements.
"I think I've stayed down that progression pathway. For me it's like finding ways to work better or do things better than I've done before and really staying committed to that."
There is also the sense that Boyle now knows what works for her and what doesn't.
Her world championship results in Barcelona last year were another advance from London and in the last two months there have been gold and silver medals at the Glasgow Commonwealth Games; and a New Zealand record three medals at the PanPacific championships on the Gold Coast.
All that must give a sense of achievement, of proving her capabilities to herself and the New Zealand sporting community.
So amid all this feeling good, no need to have a thought about the Rio Olympics in 2016 yet, right? Wrong.
"I think it's in the forefront of my mind," Boyle said.
"It's the big goal and two years out things have to start falling into place pretty well if I want to be serious about performing well there.
"I guess you would call it a medium-term goal. It's not that far away. In an athlete's life, two years is pretty close."
Here the name Ledecky comes into the conversation. That's Katie Ledecky, the 17-year-old American sensation Boyle unhesitatingly calls the finest swimmer she's raced.
The Maryland teenager Ledecky, winner of the Olympic 800m in London and world recordholder over 400m, 800m and 1500m freestyle has raised the bar like few others. Others may scratch their heads and think "woe is us". Not Boyle. Her mind is fixed on what she can do better, but not necessarily differently.
For example, this year there was a period of altitude training. That may be in the plans for next year, but perhaps earlier in the year. Boyle is still working out a programme.
"I'm going to need to swim a lot faster than my times to be in serious contention for a medal in Rio.
"In terms of physical swimming there are a few minor adjustments I could make and I think I need to be doing high quality efforts a bit more frequently than I have this year."
Boyle sees a big positive for the sport through the American's achievements.
She pointed out Welsh swimmer Jazz Carlin won the European championship 800m several days ago in a time just four seconds slower than Ledecky's best. Boyle herself stayed hard on Ledecky's heels deep into their 800m clash. All hope for the rest is not lost.
But Boyle conceded the American has a strong mental edge on most of her rivals "because her times are so much faster in some events".
She's studied Ledecky's stroke a bit, but doesn't see emulating that as a short cut.
"I have a view on technique that every individual has to do what they can with their own body to make themselves faster. Trying to copy other people doesn't usually work."
Being called the face of New Zealand swimming doesn't bother her.
"I feel honoured that people see my achievements and I guess they do stand out from the rest of the people in the team. But that doesn't mean it's always going to be like this.
"We do have other swimmers capable of doing what I've done. I have faith that they will."
