In Yesteryear: Do you recall the age old way to keep the swim fins' and mask's rubber parts supple and good condition... i.e. talcum powder liberally covering all the rubber material surfaces before dry storage in a bag. Worked good back then. Otherwise the fin and mask rubber would dry out and crack. Don't see need for that any more for same equipment. New/improved material seems to not dry out or crack. I've pair of fins some 15 yrs. old... still in good condition. Mask is 10 yrs. and going strong!
Wonder if that talcum power trick might work for storing impellers??
OTOH - With the super strong, long lasting materials in this 21st Century - Why can't they make impellers that never dry out in storage and that virtually never wear out in use. I'd pay couple hundred $$ or more for impellers that did not wear out! Gues they are made to fail so that sales of replacements continues unabated.