I've been on the Dex since early November and I'm on my 3rd sensor (well, 3rd that hasn't failed in the first day) which I just re-started yesterday. Reading are still strong and as long as I use some form of help keeping the sensor on and covering it in the shower I seem to have very few problems with it.
Usually the minute the sensor is on, I have Tegaderm over it. Once that starts wearing away I'll go with the Flexfix around the outside of it. As said, I'm going into day 9 right now and readings are still pretty dead on.
I cannot do what you are talking about. My sensor is extremely inaccurate about 20% of the time, and does not even go in the same direction as my glucose readings on my Ping meter. But if your sensor is more accurate, then you can try it. My Ping meter is always consistent. My doctor has said I need a new Dexcom.