The difference between these two sprayers is the tip that comes with the sprayer. The model name and number tells you both the tip and the length of the wand that come with the sprayer. In this case, "S" is for Standard, "CC" is for Crack and Crevice, and "24" means that the sprayer comes with a 24 inch wand. The B&G N124-S-24 comes with the standard adjustable 4-way tip which has a fine mist, fine pin stream, pin stream, and fan spray. This standard tip is the B&G Part 5800. The B&G N124-CC-24 comes with the Crack and Crevice tip, the B&G 5800-CC, which has has a fine mist, fine pin stream, fan spray, and setting for use with a crack and crevice straw (this sprayer includes the straw).
It is recommended by both our company and the manufacturers to use any mixed solution within 48 hours and dispose of any left over. Leaving the insecticide or herbicide in your B&G Sprayer 1 Gallon 24 in. Wand (N124-S-24) any longer than this time you risk harming the components of your sprayer and this also causes the product to start to break down.
Here is the the B&G sprayer manual which has an exploded diagram:
http://www.domyownpestcontrol.com/msds/BG-Sprayer-Manual.pdf
The B&G 1 Gallon Sprayer with 24-inch wand can be used for just about any of your spraying needs.