All I can say is my experience is different. I had a set of Ilford filters I used for about 20 years, and the 2.5 did not perform the same as a (never, or slightly) used 2.5 from the same manufacturer. A side by side comparison showed that the old filter had lost about a quarter of a grade. The only enlarger light it ever saw was cold light.

Unless you're trying to reproduce an old image using a print map, the change is probably moot. I likely would never have noticed had that not been the case. Following my notes didn't get me the same contrast as the original print, which is why I used the newer filters. I then did 2 new prints, one with the old 2.5, and one with the new, just to make sure it wasn't an issue with the paper. There was a definite difference.