[wim]

Wonder how long such lenses would maintain their optical quality.

The more complex the lens design, the more you have moving elements the more your lens is prone to deterioration with use, a ten year old prime, can be easily found in mint condition, this is much harder for a zoom lens (although very possible with proper care)

A lens with such a design complexity which is intended as carry on and travel lens (translates heavy stress) should be having a tough job keeping its optical quality with years.

 

As long as any other PRO lens, like the Canon and Nikon variants, if not longer considering Olympus' past.

 

Kind regards, Wim