"As the Cochrane Review notes, people generally stretch for one of three reasons:
- reduce the risk of injury;
- enhance athletic performance;
- reduce soreness after exercise..."
It doesn't seem to do any of the above, as the link makes clear.
So why stretch? Capability. If you want to be able too do x, and it requires you to be limber, you've got one way of getting limber. Do x until you're limber, or stretch in anticipation of the need.
The one stretch I do regularly is the potty squat, which I've found key to resolving my leg issues. But I am going to be doing a bit more stretching because I've gotten to the point where my lack of capability is getting annoying. The downside of a desk job.