You know I think it really depends on your imagination and the scenario you're playing. Many guys are correct that a few minutes could be the basis of your entire game based off of real life combat experience, but I'd like to point out two seperate and fairly recent historical examples from modern war that you could use as well. First, the battle of 43 Eastings pitted an armored US Squadron (Battalion) facing an Iraqi Regiment (Brigade). This was literally hundreds of tanks, and armored fighting vehicles that covered several kilometers with the US Squadron almost entirely destroying it's counterparts in approximately 45 minutes from start to finish. The second, is an operation called Arrowhead Ripper, in which a US Stryker Brigade plus and their Iraqi counterparts took back the city of Baqubah, Iraq. This operation took several days/weeks to completely wrap up. For game play it all depends on how you imagine distances and time. A house to house fight could take an extremely long time, whereas an armored battle covering ten times the distance is completed in minutes. Happy Gaming!