1. If you want to open your own business. 

2. If you help your friends and families to open a business or contribute in a current business in terms of accelerating sales, managing brands and overall branding of the particular product or services. 

3. If you work for a company in the marketing department.

4. If you work in a marketing research based organisation. 

5. In case you need to step into a marketing program out of your regular tasks. 

6. If you need to promote yourself or your work.

https://www.slideshare.net/MahimaSuri4/marketing-history-75520920

Please visit above link.