Q.Why Do I Have Brown Spots on My Pothos?
Why do I have brown spots on my pothos?

I have been an interior landscaper for 30 years, and in that time I've taken care of tens of thousands of pothos. If you have brown tips on the ends of the pothos leaves, most of the time it is indicating overwatering. Brown spots on the interior of the leaves is usually sign of a fungal or bacterial disease, and these are most often linked to overwatering also.
Before watering the pothos, you need to check the soil moisture near the bottom of the pot, not just on the surface of the soil, because the roots are mostly in the lower 3/4 of the pot. Stick a probe of some sort - a bamboo kebob skewer works well - into the soil, as if you were testing a cake. When you pull it up, you should feel the barest hint of dampness, and there might be only a few crumbs of soil sticking. Then you can water the plant.
Don't worry about misting and pebble trays - pothos grow luxuriantly in commercial situations where there is not such fuss. They are quiten content in the same environment as us.

Check out this article: https://www.gardeningknowhow.com/houseplants/pothos/poor-pothos-leaf-growth.htm