Stretching should be done for one of two reasons. One is to improve poor range of motion. The other is for specific ROM needs.
If a person is habitually tight in a particular muscle group or around a particular joint, stretching to achieve a proper ROM is wise and will help with ADL and reduce injury in and aroung that joint.
If a person has a need for a greater than average ROM, they would use stretching to achieve that ROM. As in the case of a gymnast, swimmer, etc. or for certain occupations with a specific task that requires a greater ROM.
It is possible to exceed a reasonable ROM while stretching. This is not adivsed. Joint laxity can also lead to injury.