personally I think its just that, a personal thing
some folks will run things till they get super sloppy and others will corrects s soon as they feel needed, which, they ALL have there own opinion on!
and which is why maybe no one is really saying a number on what is right or wrong here
as what I might feel is BAD others might not, and we can both be right or wrong!
the way I see things is, if your goal is LONG time owner ship of a machine, less slop is better, all the moving side to side will wear pins out faster and such, so
less slop again is best and if one can fix it, by adding a spacer, its a pretty simple fix that can add time to things and save wear and tear!
but we all cannot work on things, so this also comes down to what skill set one has , as well as TIME to do things or not!