There's no way to avoid this, no way to stay ahead of it. Every synthesizer will be retired within about ten years of its release, and then most likely some of its parts will become scarce. All you can do in enjoy being secure with a new instrument for a few years, and then, before you know it, you'll find yourself with a vintage synthesizer. I bought my Evolvers brand new; now they're practically considered relics. The only option is to constantly be selling and buying instruments, which is no way to develop a unique sound and talent.