@lumi I wanted to give some benefit of the doubt when I noticed someone with a number of years using them in a fairly proficient manner.

My regular observations with students was that the decline was pretty clear but with an expert it was not so much so I was pondering "Okay, maybe this is reasonable?"

Then tick 2 months and you start noticing they are getting slower, they are struggling to keep up with peers who aren't using them - consistency problems set in.

4 months in - they are very slow and they recognise the issues as well and they lean harder into it but a couple of weeks and there is a proper "I think I need to get my shit together" moment.

They don't use it and they start getting their speed back but it almost takes the amount of time they lost to get their capabilities back.