Hughes Heating and Cooling can help, even when time doesn't allow service during regular hours.
While there are EPA rules that mandate limits on how much refrigerant you are allowed to leak each year, these typically apply to systems with over 50lbs of refrigerant. It is very unlikely that your system holds even half that much.
On the financial side of things, it is always better to find and repair a leak than to just keep adding refrigerant periodically, This does not mean that every case will require a completely new system. Often the leak can be found and repaired, or just the leaking component can be replaced. If something you hear just doesn't sound right to you, please get a second opinion before spending thousands of dollars on work that you might not need. There are now new refrigerants that allow you to keep your existing system and change from an obsolete refrigerant.
"The repair man told that my AC is leaking refrigerant, and I need to replace the entire system. He said the government's new rules make it illegal for him to add more refrigerant to my unit."