The difference between wanting a good/service and needing a good/service lies in the level of necessity or importance attached to them in a given situation:
Wanting a good/service: When you want something, it means you desire or wish for it, but it is not essential for your basic needs or survival. Wants are often driven by personal preferences, aspirations, or a desire for convenience, comfort, or enjoyment. For example, you may want to buy a new smartphone, go on a vacation, or eat at a fancy restaurant. These are things that would be nice to have, but not having them won't significantly impact your well-being or fundamental requirements.
Needing a good/service: On the other hand, when you need something, it means it is essential for your well-being, survival, or fulfilling certain obligations or responsibilities. Needs are often related to the necessities of life, such as food, shelter, clothing, healthcare, education, and other basic requirements. For example, you need food to sustain yourself, a place to live for shelter, and access to healthcare when you're sick. These are things that are crucial for your physical, emotional, and mental well-being, and not having them can lead to significant hardships or difficulties.
In summary, wanting a good/service refers to desiring or wishing for something that is not vital for your basic needs, while needing a good/service refers to something that is essential for your well-being, survival, or fulfilling critical responsibilities. Distinguishing between wants and needs is crucial for making informed decisions about how to allocate your resources, time, and energy. Prioritizing needs over wants is often necessary to ensure you address the most critical aspects of your life first.