A/c as in air conditioning? Most likely It doesnt NEED to be replaced unless you NEED/WANT your a/c to work.
Truthfully, anyone who can turn a wrench and pop some quick disconnects apart can change an a/c line. The thing you have to watch is handling the refrigerant. I imagine you have an r-134a system. You can simply buy little cans to refill your system but you are "supposed" to reclaim what is in your system instead of letting it into the atmosphere and popping holes in the ozone. be careful because that stuff will give you freeze burns and could make you go blind if you are not careful.