Smyth-sewn (sewn) case binding—most durable, strong page retention, and naturally lay-flat. Need 180° use? Choose lay-flat case or concealed Wire-O. On a budget or tight timeline? Perfect binding is clean and economical but less durable/flat. For thick books pick sewn; for planners/manuals choose Wire-O/spiral. Decide by use case, page count, paper gsm, and budget.