Since the release, on starting the sim, I’ve always gone into my Task Manager’s Details and set the Priority for MSFS at “High”, manually. I’m not really sure if this helps the sim in anyway but question is…
Does this help the sim perform any better compared to leaving this setting as is or is it just considered bad practice from the start?
In my experience, it helped avoiding crashes to desktop when they still were a problem for me.
Since the last couple of patches, they’re not an issue anymore, and changing priority has no visible advantage, so I stopped doing it.
You normally shouldn’t do that. A well-optimised, multi-threaded application will not benefit because there will be threads that will be started with higher priorities as required and designed by the devs.
By starting the sim in high you are putting more threads into the high priority, thus interfering with the entire logic.
However, it could help avoiding for example the impact of running other apps on your system.
I’ve tried toying around with Process Lasso checking things like this and nothing had any effect whatsoever. 
I have done this and it made no difference whatsoever.
I have never done it, and MFS runs ok.
Thanks all. Think I will take the advice and “Live and let live”. 
Recently found I have had to set priority as high to avoid CTDs when loading a flight plan.
Made no difference for me.
Tried it today and guess what, high priority or not Windows 10 controls MSFS priority as needed. Stetting it High or Normal makes NO difference (at least in my system)