I think I would say that beaches are changing all the time, but very often the changes are just like the last time. Exactly what changes a beach depends on your location - in some locations, weather patterns means different kind of waves as season change. That definetly moves the sand to a different position. In other locations, moon phase is quite important. I live 10 floors up from the sand of one quite well known beach and having watched it for a year now I am just short of testifying that every time there is a new moon, the beach looks almost the same. At that moon phase, it is really not good for surfing as all the sand seems to be shuffled up onto the beach and the waves break about 1.5 meters out, sending all their energy right down on the sand. However, when the moon is in the opposite phase, I can give you a quite good prediction for where a rip current channel will form between two sand banks extending along the beach to each side. Then, if the waves come in moderate size and the common direction, there is decent surf to be had with waves opening up on the side of the sandbanks, with some extra distance if I am able to hit that rip current channel. Only at high tide I can ride directly across the sandbank. All this happens in loose sand, but it seems to stack up at the same location every time, after moving around a little.