Advantages of friction:
1. Friction enables us to walk freely.
2. It helps to support ladder against wall.
3. It becomes possible to transfer one form of energy to another.
4. Objects can be piled up without slipping.
5. Breaks of vehicles work due to friction.
Disadvantages of friction:
1.It always resists the motion, so extra energy is required to overcome it.
2.It causes wear and tear of machines.
3.It decreases the life expectancy of moving parts of vehicles.
4.Since friction is very useful in some cases while harmful in some cases, friction is called a necessary evil.