The TMP117 datasheet specifies: Long-term stability and drift 300 hours at 150°C ±0.03 °C
We subjected a sample of TMP117 devices to the stated stress (300 hours powered-on operation at 150C) and observed the 0.03C variation. This is a standard operating life test defined by JEDEC. The high temperature accelerates aging; the Arrhenius equation calculates the equivalent time spent at a lower temperature. See Arrhenius in the following document: https://www.ti.com/lit/snoa994
Solving the Arrhenius equation for 35C application temperature using a 300hr/150C stress results in 44 years of simulated aging.
The model can produce very large numbers for low temperatures. Some other temperatures worth noting: An application temperature of around 53C results in about 10 years simulated aging. An application temperature of 85C results in 1.1 years of simulated aging.
We also have data for a sample of devices aged 1000 hours at 150C, and plan to update the datasheet to reflect 1000 hours +/-0.03C soon.