Why does the nailpolish on the tips of my nails always chip off? I use a top coat!!!?

because we as women use our hands for everything, and i hate having to polish every other day i don't think it matters about the top-coat its something we have to do. i stick to really basic shades pearlized white, pearlized bronze because if i go dark my nails turn yellow plus i like the sheer shades for summer very sexy! and here is another thing who in the world thought black was a good color, c'mon ladies!