The maintance of the rock istelf is fairly stright forward. Provide water conditions that are consuive to keeping fish and wala you are maintaning the live rock. Now there are different levels of maintaning it. You have the baisic maintance as far as the live rock as a home for clean up crew worms and crustations as well as bactera. This kind of maintance is basicly done at the water quality level.
Then you have keeping the rock looking nice (corline algae and other algae growths). For this ample light and calcium levels would be in order. Light does not need to be at the level to keep corals but does need to be more than maybe a single or double florecent tube. (depending on tank size and depth)
The last stage would be acutally encuraging coral growth on the live rock. Most of the live rock has to some extent the potental to grow some kind of coral. Small corals might have been growing on the rock in the wild and could still exist on the rock in our tank after shipping and such. and to maintan rock in this maner than you need the higher output lighting and the higher water quality that corals themselves need.
The basic truth is that its not hard at all to maintain live rock and keeping your tank in the condition to keep your fish is the biggest part of the equasion.