You should also factor in how each user has been using their display differently.
Mine for example, had a period of 75% Brightness enabled with HDR as well as I gamed a lot, and I had not yet employed a darker scheme for the window borders and menus yet. Only a black/unlit background. What this did, was then create a noticeable band where the borders and menus were pure white. It was after this period of merely a few weeks that I noticed image retention/burn, but only visible on a grey scene and it only appears as a slightly darker residue where those borders and menus were located.
Someone else who had a mostly lit/bright screen that constantly had motion and little static elements, may have more uniformly "burnt" their screen and made it less noticeable.
There's lots of variations in between. So it's easy to see how some could have found their screen had burned in parts, whilst others may not notice anything visually.
Desktop wise.
- I have wallpapers that change every 10 minutes
- using start all is back which hides most of the grey bar but I don't hide the taskbar
- windows aren't fullscreen, sized in such a way so as to either be more in centre or maybe 2 windows open side by side i.e. youtube videos on one side then browser on other
- Screen saver of just black wallpaper after 10 mins
Essentially I haven't baby sat the monitor in any way whatsoever and would say I've been a very heavy user, similar to mrks (although probably far more gaming on my side and less static windows for longer periods of times prob, which is likely where his has come from) yet he has gone through 4 now I think.
Same with my LG e7 too (had since 2017), there is no signs of permament image retention, usually some very temporay IR from logos/huds but it goes fairly quickly after watching something else for a bit.
Certainly hasn't been anything noticeable in normal usage anyway and very pleased to never have to go back to lcd again.