The use of the plural "wars" may indicate that cease fires, treaties and declarations of war took place more than once. This also helps to explain the seemingly confused dating.
This was at some point between the mid-2340s and 2355.
Losses during the wars left deep scars on both sides. For instance, Gul Evek lost two of his three sons during the Cardassian Wars, and Captain Benjamin Maxwell lost his entire family. Starfleet officers such as Will Kayden and Raymond Boone died during the war. Popular Federation ambassadors Spock and Sarek (Spock's father) disagreed publicly over the Cardassian Wars, which led to a serious divide in their relationship and family. (TNG: "Journey's End", "The Wounded", "Unification I"; DS9: "Tribunal") Tensions remained between the two expanding powers. Many seasoned veterans from both sides were called upon by their respective governments to face each other again during the Dominion War that began in late 2373.
From what we know of the Maquis and the DMZ, it seems this war started because the Federation and the Cardassians colonized a number of class M planets in proximity to each other. Both sides seem to have recognized a different border line. The Cardassians sought to annex several crucial worlds along the border, perhaps because of the same resource shortages that had led them to the Occupation of Bajor, while perceiving Federation colonization in a similar context.