Lifespan was never a concern for Boundary Breakers, for unless they died by accident, there were plenty of ways to extend one's life in the Great World. Such welfare guarantees made the Boundary Breakers quite willing to spend years, even decades, in exploration.
Soaking in the Spring of Life not only restored their consumed lifespan—although it wouldn't break the original lifespan limits, just restore it—but it also granted additional strength enhancement during the soak. Such enhancements could be much greater than the strength they would accumulate over several years, or even longer, in a world, with very few side effects.
At most, due to an insufficient physical foundation, they needed enough time to digest the benefits. Opening up a new world was just such a digestive process.
