Don't cycle ECA... there a lot of people that have this seriosly wrong. checkout
http://www.drumlib.com
I tell you this because I did the same thing... and every time I went of the shit I would get a huge headache from the caffeine withdrawal. Infact its good to keep taking it so that you can build a tolerance to the caffeine.. no it will not stop working because of chronic usage. Cycling make you go through all the adverse side effects each time you cycle... not fun.
Yes start slow... but don't cycle
The serious thing that you have to watch out for (in my opinion) is the caffeine. If you have not been drinking coffee or soda regularly the caffeine will be quite a shock to your system. People make a big deal out of the ephedrine but I swear that much caffeine... can cause some serious insomnia/jitters/ so on...