How to caulk or recaulk a bathtub or shower enclosure?

Don't ignore loose caulk!
In a nutshell, caulk is used in a tub or shower enclosure to keep water from creeping up, under or around the tiles at joints between tile and the tub or shower pan, or on joints where walls meet. Leaky caulk is not to be ignored! I have often seen tiled bathrooms where the two or three bottom rows of tiles

With all those other great glues, why should I bother having wood glue in my workshop?

Good question! You would think that with the chemical marvels described above a water-based wood glue would have gone the way of the dinosaur. You couldn't be more wrong. In its own element... that favorite of termites cellulosis dinnerosis (a.k.a. wood)... good ol' wood glue... is as strong or stronger than those other fancy-schmancy adhesives.