If you're printing a booklet, book, or multi-page report you need to plan how the finished product will be put together before you set up your document in your page layout program. For some types of binding it might simply be a matter of ensuring that the margins are wide enough to accommodate the holes for a three ring binder or spiral binding. For saddle-stitching, you may need to compensate for creep. Some bindings are more durable, others allow your book to lay flat when open. You'll also want to weigh the cost of special equipment if you want to do-it-yourself rather than using a local copy shop or printer.
No discussion of printing would be complete without mentioning the variety of binding styles available. Jobs have been destroyed in the bindery due to the lack of planning or because the binding process was taken for granted.