I stopped matching thread to fabric in quilting when I started going scrappy, there simply was no way I could match. Now I am typically threaded with a steely blue/grey and light beige/camel. I use the two different colors so I can more easily see the stitches if I am looking for them, both both blend into other fabrics. If I'm doing darks, like say black and dark batiks, I will use up what I have left of dark threads -- Oh, look over there, enough of that hunter green to wind a bobbin, let's go!
For the quilting thread, the traditionalist in me fought for a long time that the only proper color was white. Now, I'm like what the heck? You want to show off the quilting use (complementary) fuchsia thread on aqua cloth and go for it! Maybe not me so much but I will at least consider it
I think one thing my vision lost has taught me is the value of contrast. Not just in colors or in values, but also scale of fabrics. Again, my inner traditionalist self loves tiny vine-y calicos, but they all blur into one another without some solid or stripes or large prints. Blur is good when you are doing watercolors or low value, but not so much when you want those lovely pieced points to show off.
It (the vision loss) has also taught me to appreciate some looser construction methods, like the slice and dice crazy project I'm currently working on. I do my best to keep points sharp and such, mostly by cutting the fabric large and trimming down the subunits to perfect size.
Likewise, in reality we are too close to our projects. We need to step back from that 6-inches away inspection to a couple of feet. And of course, on a galloping horse if needed.