iPhone Upgrade Cost Comparison

計算原理與數學公式

Total Cost of Ownership (TCO) Formula (3-Year Horizon):

1-Year Cycle TCO = 3 × (New Phone Price - 1-Year Trade-in)
2-Year Cycle TCO = 2 × New Phone Price - 2-Year Trade-in - 1-Year Trade-in
3-Year Cycle TCO = 1 × New Phone Price - 3-Year Trade-in + Battery Cost

Note: For the 3-year cycle, we assume one battery replacement to maintain peak performance. For the 2-year cycle, at the end of year 3, the current phone is 1 year old, so its remaining value is the 1-year trade-in value.