Smoke testing and sanity testing are both essential techniques in manual testing, but they serve different purposes. Smoke testing, also known as build verification testing, focuses on quickly checking if the critical functionalities of an application work correctly. It's like making sure a car starts and runs smoothly before examining other features. On the other hand, sanity testing verifies specific aspects of the software after changes or fixes, ensuring that the modifications haven't broken the core functionalities. It's like a quick check to see if the car's engine still runs smoothly after a tune-up. Understanding the distinctions between these testing methods helps testers ensure the reliability and stability of software applications.