Ankles sprains are the most commonly sustained sporting injury. As an example, between 70-80% of basketball players have had at least one ankle sprain. Like Steph Curry for example.
Troubling statistics came out of a study from 2016. 25% of people still have pain six months after their first ankle sprain. 30% of people report regular pain, swelling and recurrent injury up to seven years after their initial ankle sprain.
The most likely reason is that the ankle sprain is often not rehabilitated well or even at all. Once the swelling, bruising and pain has settled down (thanks to your good acute injury management) the ankle might feel ok and so the tendency is to return to sport. But the swelling, bruising and pain are only some of the issues that need to be addressed after you sprain your ankle, even if they might be the most evident.
What else needs to be addressed?
It depends on the exact nature of your ankle sprain, but there are a number of other aspects of the ankle's function that get impacted when you sprain your ankle, such as:
Loss of normal range of motion
Impaired proprioception (joint position and movement sense)
Reduced muscle strength
Reduced stability of the injured ligaments
A proper ankle rehab will assess and address these factors to better prepare you for safe return to sport. Failure to address these issues increases your risk of ongoing pain or recurrent injury in the ankle, as well as increasing your risk of other injuries as impaired ankle function is likely to alter your biomechanics.
It's also recommended that an ankle stability brace or ankle stability taping is used during sport and other activities that represent an increased risk of ankle sprain, for six months after the injury. It was previously believed that using an ankle brace or taping may result in 'weakening the ligament' but recent evidence suggests that it does not have this effect, and that the opposite may be true, by allowing less lengthening of the ligament as it heals.