Please help identify what's the problem

I am sure this is in the wrong category, but i'm at a loss as to where to post this. This plant has had this problem with its leaves for a long time. They turn silvery and sometimes shiny and then fall, see the image included, any help will be appreciated.

Thanks.

Thrips. Very tiny insects, like aphids, that scrape the surface of the leaf in order to feed on the juices. Often with plants like rhododendrons that keep their leaves for a long period of time, the damage is cumulative and by the time it reaches that silvery state, the leaf is about ready to be dropped anyway. If there are lots of unaffected leaves still available for photosynthesis, then it can be left alone.

If you get an infestation to the point that leaves are dropping off faster than the plant replaces them, you could intervene by spraying with soapy water or a dormant oil.

Thank you Phil Stevens.
I will go ahead and spray them with soapy water, the condition is pretty wide spread throughout the plant and has pained me to see it this way for a long time.
I appreciate your suggestion!