Before I keep forgetting to put this here for you:

You can measure your screen distance once properly, and then set yourself up a little system to keep track of changes in distance.  As per a great post in our group:

There you go.

There’s also plenty more on measuring, over in the wiki.

For a million more tricks and ‘shortcuts’ (there are no shortcuts) and helpful insights and community, support endmyopia with one of our awesome courses.

Cheers,

-Jake