Ester is not the problem. Homeostasis is the issue. Over time, your body is going to get used to any dose you take. If you go from taking nothing to taking 500mg EW, your gains at first will be great. Over time, it will become less effective. The only thing you can do is either, lower the dose for a period, or add more gear. As I'm sure you can see, there is going to come a point that adding more would not be a wise/healthy choice. Your best bet for cruising periods, is to take the least amount that you can use to maintain your quality of life, keep healthy, and maintain your muscle mass. I'd shoot for around 800ng/dl. Most guys can achieve this with around 200mg EW.
Give yourself periods at these lower doses. Allow your body to readjust and get used to haing test in the normal range again. Then plan your cycles for a period of time. running gear harder, followed by backing down to cruising dose again.