Lu Yuan is now in the Gather Two Qi phase, which he has been in for fourteen years; this is equivalent to 120 years for an ordinary person with the same qualifications, yet he still cannot break through.
He estimates that it will take about three to five more years, or roughly twenty to forty years for an ordinary person, to complete this accumulation.
Thus, for an ordinary person with the same qualifications, it would take approximately 150 years to progress from Gathering Two Qi to Gathering Three Qi.
Adding on the time it took to break through the previous two realms, an ordinary person of medium aptitude, who has a lifespan of 300 years during the Gathering Two Qi, would likely only break through to Gathering Three Qi between the ages of 270 and 290.
It's akin to barely making the breakthrough, lucky to hit the limit of one's lifespan.