When to change out that old shower

Sometimes the shower damage is to extensive and the shower may need to be replaced.  There are times when the damage is just in the curb, or the slab is too contaminated with calcium to be fully cleaned.  In these situations we are able to remove the tile from the shower floor, remove the slab, and then clean the drain.  Schluter makes a drain that we can install to the pvc flange as we pour the new slab.  We can then add a piece of kerdi liner to the floor and re-tile.  It is important to note that this is not a full kerdi shower with all the benefits of the waterproofing going up the full wall.  We still rely on the weep holes to clear the water that wicks through the walls and down into the vinyl liner that is still there as well.  But we have put a waterproofing membrane on the floor part of the shower which greatly reduces the amount of water that gets into the slab.  And then sometimes we have to remove the entire shower.  This is when we find damage to the sub floor that can not be repaired with the vinyl liner in place.  There are also times that we find damage in the wall structure as well.  The unfortunate thing is that this damage is not always visible until we start taking out elements of the old shower.  Jen, why don't you comment a little on how the design of tile showers has changed in the last 5-10 years?