What should I know before adding colored examples?

A book with colored pages must be printed with a color interior on KDP (standard or premium color), which costs more per copy than black and white. The Print check says so: "N colored examples are in the book: choose a color interior (standard or premium color) when you publish it on KDP. Color printing costs more per copy than black and white." The cover wrap in Covers then opens with color paper. In a single-sided book the example is printed on the back of the page before, so markers used on that page may show through it.