DIY visual marking

[Green]

I've used sticky dots on the microwave and cooker knobs, also fine tip permanent pens on dark objects like a remote, or to make openings or ports more visible in yellow or silver.

[gsward]

That's a great "low tech" solution for a visual/technology problem. You can extend the idea with different colours for specific purposes.

Conversely, I find emojis a nightmare trying to differentiate the different faces!

[Green]

Yeah I know what you mean, some things/sites are harder than others.
An idea from my dad is to punch holes in a bunch of keys, like 1, 2 or 3 on the bit you hold to help differentiate. He used to be an engineer so can do that in his garage, but I reckon shoe repairers/key cutters could do it. Its quite useful with a bunch, a bit like braille for an object.

I also use a headlight on a head band to enable hands free access to do something where I need more light.