Beauty and cleanliness can affect the life of someone a surprising amount.
Usually, if someone believes themselves to have beauty, then they are much more likely to have a strong sense of self confidence. This alone can change how you live your life.
Being more confident at work can set you apart from other employees, and can lead you to a promotion. Being self-confident is an attractive attribute to an employee and also potential customers.
Cleanliness and beauty is also one of the most attractive qualities to a romantic partner. Not only will you feel better in yourself and willing to meet other people, but it can also draw people to you. If you smell great and look great then you are much more likely to have more luck in the romance world.
An example I can think of on a day to day basis is when I have greasy hair. When I go out and I feel my hair doesn't look and feel as good as it could do, I don't want to see or meet other people. I am less likely to put myself forward for things, therefore not get so many opportunities.