The U.S. Army had actually come up with a peacetime method of keeping readiness real. This was done with the training centers that allowed very realistic testing using weapons equipped with lasers, and laser detectors, to accurately measure the effects of firepower. This made the same old wargames a lot more realistic. As was discovered during the 1991 Gulf War, this made American ground combat units as effective as battle hardened ones. But the non-combat units found that they still had to adjust their concept of readiness.
Came the Afghanistan and Iraq campaigns, and combat support units again found that peacetime and combat readiness had drifted apart. This was particularly the case with logistics (getting supplies where they were needed) and maintenance (fixing stuff that broke down in combat). You dont hear much about changes in maintenance and logistics, but they have been many and frequent in the last three years. Perhaps more importantly, the readiness of the different services to operate together (jointness) has also gotten a wake-up call. Lack of readiness for jointness is an old problem. Everyone agrees it is needed in wartime, but the services drift apart in peacetime. This time, joint training and readiness is being institutionalized as a peacetime need. No one is sure that the services will continue training together, as much as they need, when peace returns. But at least everyone is saying that is important and that they will stay the course in the future. Time will tell.
Readiness is one of those military terms that is supposed to mean how prepared a unit is for combat. In peacetime, the standards tend to drift from reality. With no real combat to really test readiness, what passes for readiness is often more illusion than reality. Comes a war, and what really constitutes readiness becomes obvious.