Here’s another example of how an unexpected change can affect a photographic subject for many years.
There is a great water wheel at Cable Mill in Cades Cove in the Smokies. It had been quite photogenic, especially with its thick coating of moss. Here’s an image of the wheel made in April 2014.This photograph of the wheel was made in May 2018. The paddle boards had recently been replaced, making the wheel much less photogenic. It will be years until moss fully coats the wheel again. In fact, there was no reason for me to even make this photo except to illustrate what can happen if you don’t make an image when you first see the possibility.
If you make an image, you can always make a better one later if the light, the conditions, and your equipment are better. If the subject later changes or is gone, you’ll always regret not having made the image when you first saw it. Shoot it now.