We report measured wavelength shifts of over one hundred 1.5-mum DFB lasers aged under three different conditions for a period corresponding to the system's lifetime (approximately 25 years). The results show that the lasers aged at lower temperature (thus higher optical power) have wider spread of wavelength shifts than the lasers aged at higher temperature. No correlation was observed between the wavelength shifts and the aging rates or the aging-induced changes in the threshold currents. The aging-induced wavelength shifts were relatively small (+/-1 angstrom) for most lasers. However, about 10% of the lasers exhibit larger wavelength shifts of up to about +/-4 angstrom.