Despite the war on terror, American armed forces have been maintaining the same high "crew training" levels that have, for the last two decades, made them the most effective troops on the planet. This year, each American tank crew will take their vehicle about 1,500 kilometers in training exercises (plus dozens of rounds fired from the main gun and many hours in simulators ). Army air crews will spend 157 hours a year in the air, compared to 250 hours for navy crews and 202 hours for air force crews. Navy warships will spend, on average, 216 days at sea. The navy flight crews get more hours in the air because carrier operations are more complex and additional hours are needed to maintain skills. The army has fewer hours because most army aircraft are transport helicopters, what do not require training for as many different operations as combat aircraft. In addition, any crews in a combat zone will get a lot more time using their vehicles. This is an unspoken benefit of combat, as it makes the troops involved much more expert in the use of their equipment and weapons. 

Most industrialized nations match, or come close to, US training levels. This is because they can afford it, and it's long been recognized that this level of training pays off when the troops have to actually go into action. But most countries cannot afford the expense of training. It costs thousands of dollars an hour to fly aircraft, even more per day to keep a warship at sea, and over a hundred dollars a kilometer to run a tank. Many nations can afford to buy the tanks, aircraft and ships, but find they cannot afford to let the crews use them much. This is the main reason why troops from industrialized nations so often quickly defeat those from less wealthy nations. It's not just a question of money, but how you use it.