Hopefully you can see why I think my master bath was done in '39.
Here's the summary:
-My sink is pre-war Crane Drexel. Major additions were done in '39 so I would guess the sink is from '39 or '40.
-The master bath was originally a changing room. That's why it has a closet and a redwood vanity desk. That is a very old fashioned feature more in line with the Victorian era of body shame
-the shower is white square tiles (fits with '39). The trim is like the kind in the '50s bath above, probably popular from the '30s-'50s as it has a hint of Deco style.
-the floor has no hint of tile, just linoleum, which means the floor was originally redwood (probably) like the rest of the house, then at some point, probably in the '60s they added linoleum and mosaic tile in the shower pan.
-the mosaic tile in the shower pan is super '60s. No doubt about it. Blue and green, under 1" squares and rectangles in "random" pattern.