I have two mouth calls, a H.S. Strutt Double D and a Primos Thunder Dome. I just learned how to use them this season so I've only used for approx. one month. This past weekend I've noticed there are now small tears on the leading edge of the latex and being very new to using them, I'm not sure if this is what is meant to being "broken in" or if maybe using them for crow calls b/c that involves quite a bit of pressure and blowing fairly hard (this causes alot of high speed vibrations on the latex). Am I ok with these or will they worse. What is the time frame of use with mouth calls. P.S. I only call while hunting every 10-20 mins but at the house, as my wife states, continuously while practicing.