While an adjustable wrench can sometimes work for easily accessible nuts, a basin wrench (like the Husky Basin Wrench 16PL0127 mentioned) is highly recommended. It's specifically designed to reach and loosen mounting nuts in tight, awkward spaces under the sink, making the removal of the old faucet much easier and less frustrating, especially for beginners.

Absolutely ensure both the hot and cold water supply lines are completely turned off at the angle stops beneath the sink before you begin any work. Test by briefly turning on the old faucet to confirm the water flow has stopped. Keep the Unger 6 Gal. Heavy-Duty Plastic Bucket ready to catch any residual water when disconnecting lines.

For stubborn or rusted nuts, first try applying a penetrating oil like WD-40 or Liquid Wrench and let it sit for 10-15 minutes to help loosen them. If they still won't budge, you may need to carefully use a hacksaw blade or a rotary tool with a cut-off wheel to cut through the nuts, taking extreme caution not to damage the sink or supply lines.

The 'beginner' difficulty refers to the straightforward nature of the tasks, not necessarily the speed. The 3-hour estimate accounts for potential real-world challenges such as tight working spaces, rusted nuts, properly reading new faucet instructions, and thorough leak testing. Rushing can lead to mistakes, so taking your time to be meticulous is key.