User blog comment:Xilinoc/Ch. 682 - The Two Sided World End/@comment-26091912-20160713132058/@comment-5398287-20160714130728

Urahara's Shikai and Bankai are linked by the theme of "adaptation". Shikai has a ton of different techniques so Urahara can attack, defend, or restrain depending on what needs to be done at that moment; Bankai, on the other hand, lets Urahara directly alter himself, his opponent, and the battlefield in response to changes in the battle and to his opponent's abilities.