I have to hard half-and-half disagree about your point wherein if you have a dedicated prescription mask and your prescription changes, you need to replace the whole thing. I need heavy prescription lenses in my glasses to see overall, I have been diving my same Tusa Paragon mask (two separate lenses, not the single lens ones) frame since I have started diving and its still going strong. The best part is that I have the option to easily order individual lenses of different oculus dexter (OD, right eye) and oculus sinister (OS, left eye) strengths. They do them in intervals of -0.5 but its a very close approximation of my most recent prescription. Each lens is $60 and will last me about two years, especially since the water also helps to further magnify my vision. The best part is that when I get my new prescription, I can easily disassemble the frame, remove the lenses, and replace them with new ones. And at a significantly cheaper rate than getting a new mask. I speak strictly from my personal experience with Tusa masks and I am unsure if other mask brands offer these options and flexibility. Proceed at your own discretion, but know you have different options, this just happens to be what works for me.