Is caulking necessary?

Hi all, today I removed some caulking from between the tile and tub on a tub/shower. It suddenly donned on me that when the water gets through the grout/cement board and goes back to the tub, how does it get back in if you have that interface caulked? Then I did some googling and found this.....

"It doesn’t need to be caulked at all. Caulking at the bottom of the tub is not a required step, it’s more aesthetic than anything else. Although it does contain more water in front of the surface of the tile, you don’t NEED it."

Even if I left little area's uncaulked (weep holes) wouldn't the water get in behind the caulk and eventually get moldy?

Thanks,

Mike

A properly built shower is waterproof before you install the tile. Industry standards call for caulk at the changes of plane. Mostly, this is to prevent high volumes of liquid water from getting into the setting surface. They are better served by water vapor and small amounts that may get there by wicking unless you use a surface waterproof membrane underneath the tile. A good caulk doesn't support mold. Now, that doesn't mean that soap scum, and whatever may not get ON it and then support mold, but the caulk itself (especially 100% silicon) doesn't support mold. Since it's hard to clean those crevasses, caulking them means less is likely to get in there to accumulate and then support mold.

Thanks, must get the 100% stuff !