In quickstart of the documentation it says:
The Blender/Python API can’t (yet)…
- Define callbacks or listeners to be notified when data is changed.
However, callbacks on data changes are possible according to the Properties documentation:
Are these 2 pages talking about a different aspect or is it a conflicting statement? I went looking for ways to trigger functions on data change, but started to look outside Blender for ways to do that due to quickstart doc. However, by chance, I stumbled on the other page to find out it IS possible in Blender.