If a book is being perfect binded, wire, coil or 3 hole drilled, it will need bleed on all four sides. So do not use facing pages on these binding methods and extend the bleed on the spine side as well as the other sides.
On thicker saddle stitch or perfect bound books, please allow a larger gutter since that area will creep into the binding.
If you have a large, saddle stitch book (especially with thicker paper), keep your face margins at least .375 inch. Although printers have means for adjusting this, saddle stitch books need extra room for the outer pages to wrap around the inner pages. If page numbers or copy are too close, they could run the risk of getting cut off or be closer to the trim than expected at the beginning and end of the book.