Since there are waiting times between meat and milk (roughly speaking 6 hours for Polish/Russian Jews, 3 for German, 1 for Dutch, though many families have slightly different customs), if I know I'll be having dairy later in the day-- a coffee date, perhaps-- I'll opt for a dairy meal earlier as well. This leads us to the greatest Jewish fear: F.O.F, or Fear of Fleishiks (meat). I rarely eat meat for lunch, because it would limit my options later in the day. And I will almost always value a potential ice cream break later in the day than a deli sandwich now. There is a short waiting period after milk (15 minutes or washing out the mouth), so either milk or pareve are good options when you don't know what denomination your next meal will be.
Along with the pots and pans come silverware, dishes, and cooking utensils, which are similarly doubled. To sum that up, in my kitchen there are 2 sets of pots/pans, silverware, utensils, and 3 sets of dishes (dairy, everyday meat and formal china, which are meat as well). Luckily, glass is considered nonporous and glasses can thus be used with either denomination. I think the ancient rabbis simply ran out of space and came up with that rule.
And finally, when your meal is done, time to wash those dishes. With separate sponges, of course. Since I only have one sink that gets both milk and meat particles, I place different sink ranks inside for meat and dairy inside when dishes of either denomination are soaking or being washed.
Up on tap: Uh oh, I screwewd up: What to do when you dropped the meat spoon into a pot of milk; shopping for kosher groceries, how and where to eat out, and whatever else you're interested in learning about. Let me know!