Just to add my 2c, mine failed 2 years ago at around 100k.
In my case - apart from feeling of car's sluggishness, I could observe low boost and TCV duty cycle off the charts, when testing with Vida.
I am not sure if those really loose performance in time (i/e. if not broken, will it work worse just because its old? ) but for sure its one of most critical component to keep turbo piping in good condition and defo one of the cheapest to replace.
Also - worth adding - replacing CBV (that small metal valve going from turbo to piping) made quite a difference on mine.