I think much of the cheap mass market stuff is on the low end of the list. I also realize that much of the supplements you take, even the high quality ones, do end up being eliminated anyway.
However, there are many studies show the effectiveness of various substances to help prevent or treat various conditions. For example, resveratrol, indole-3-carbinol (I3C), leutine, various lignans, phenols, polyphenols, cyanidins, and so forth have been fairly heavily researched.
Personally, I take the view that the body will do the best it can with what it has, so why not make sure it gets some effective nutritional help from time to time so it can perhaps ward off common issues better. For example, macular degeneration happens to a fair number of older people, but this condition appears to respond well to lutein and zeaxanthin.
Lutein and age-related macular degeneration
There may be some scientific sense for these results. There seems to be a link between age-related macular degeneration and oxidative stress, some from the actions of light on the retina, and some systemic. As with heart disease, cancer, and other disorders, diets with higher levels of antioxidants, or antioxidant supplements, or both, are associated with less chance of the disease. It is the old healthy living message about eating plenty of fruit and vegetables, getting some exercise, not smoking, and having the odd medicinal glass of what you fancy.
Lutein is a yellowish pigment found in egg yolk, some algae, and in many plants. Zeaxanthin is found in small amounts in most fruits and vegetables. Both are found in the retina, and both are found at relatively high concentration in the macular region of the retina. Zeaxanthin is preferentially found in the foveal region and lutein in the perifoveal region. A systematic review  examines how these two pigments might be related to protection against macular degeneration.
Lutein and zeaxanthin may protect the retina in two ways, as antioxidants to oxidative stress from metabolism, and, by filtering short wavelengths of light they also reduce the oxidative effect of blue light.
There are a number of studies that indicate a lower risk of macular degeneration associated with consumption of lutein and zeaxanthin, with their levels in diet, or higher levels in the blood. For instance, in a good epidemiological study of 380 people aged 66-75 years in the UK , people with lower blood levels of lutein plus zeaxanthin were more likely to have age-related macular degeneration (Figure 4).
I’m sure there are many other sources of information than this thing, which came up near the top when I googled for macular degeneration. So, if you supplement with various nutrients it appears that you can lower various risk factors. No guarantees, but if you are prone to developing a condition and don’t supplement to fight it, then what choice does your body have?
Considering that my grandmother has suffered vision issues in her old age and that I’ve had laser surgery which surely stresses the eyes, I’m happy to knew that my multi provides these nutrients as well as many others.