Calculating resistor end-of-life drift in the worst case analysis
If you had an expensive 0.1% tolerance resistor, you might be concerned.
The drift is given for burst loads a 70% power or P70 and and aging rate of 30’C rise per order of magnitude reduction in MTBF.
What you ought to learn is that Resistors are usually rated for 125’C or a 100’C rise above 25’C, while 85’C will burn your finger but is an acceptable good design limit.  That would be 65% rated P above 25’C
If you were really concerned about drift, you would choose a larger power rating and not exceed 50’C and could ignore the PPM drift in the next 10 years.
But if you only need 1% tolerance chances are very high that it will always stay within tolerance if you limit T max to 60’C.