Based on the lifespan mathematical model L=Tavg ×N proposed in SFL-LS-01 and the G₀ ΔGd cellular damage system from SFL-CELL serial, this paper elaborates the core rule of finite lifetime cellular renewal quota N. N is an inherent constant determined by human species traits at birth and cannot be increased artificially. The remaining usable lifespan follows the derived relational expression: Remaining lifespan calculation formula Remaining Life = (N − Cycles Used) × Tavg Irreversible ΔGd(-) structural damage to cellular G₀ modules shortens average functional cycle Tavg, forcing the body to trigger frequent cell replacement and consume the fixed quota N at a faster rate. Three major categories of factors that accelerate quota depletion are systematically sorted out: intrinsic cellular G₀ fragility, external environmental toxic stress, and sustained chronic inflammatory circulation. A standardized controlled case comparison under unified baseline N=10 is provided for demonstration. Healthy individuals with intact cell G₀ structure hold Tavg=8 years to gain an 80-year theoretical lifespan; individuals with severe cumulative ΔGd damage suffer suppressed Tavg=4 years and only a 40-year predicted lifespan, which directly explains individual gaps in aging speed and disease susceptibility. This paper clarifies a core anti-aging orientation: longevity relies on preserving cellular integrity rather than boosting regeneration efficiency. All chronic pathological accelerated turnover phenomena cited in follow-up LS papers originate from the G₀ module collapse mechanism summarized in SFL-CELL, forming a complete logical chain linking cell structural damage to total lifespan consumption.
FOO SENG ANG (Sun,) studied this question.