My experience has been since 2006 that if I need to keep a Festool CT running for an 8 hour shift, it will do so without damage.
With Festool sanders I almost always use the auto start function with the CT, and I assign a separate CT to each sander being used because the suction setting is an important function of sanding. However, when I am using the Domino, TS saws and most routers, I generally turn on the CT at the start of the session and turn it off at the end of the session. Same too with the KAPEX.
I have owned my original CT22 since early 2006. It has always been used this way and has never required factory service, just commom-sense routine maintenance.
In my opinion, Festool dust extractors are rated for contenous duty.