How much cooldown/stretching do you do?

I've pretty much eliminated cool down after a swim or bike as I just never really noticed much difference and is not a great use of my limited time.

I have increased my cool down after running which is something that I have found to be very beneficial.  I plan my route so that I end about a half mile from home and walk to cool down.  Sometimes I'll even do a few stretches. 

Swim: I like to end my workout with some under water set, usually 8x25, it really relaxes me. 

Bike: On the trainer 10min easy spin on gearing down. 

Run: Run/walk home from the park, 8 min. 

I usually don't stretch after the workout, running in the cold I care more about getting a hot shower. I don't feel the need after swimming.

Once a week or so I do a pilates/core strength workout and end it with 20min. stretching the whole body through.

Yup...I want to get faster...not stretchy.

What exactly about swim bike or run requires flexibility beyond normal range of motion?

Swim: I usually finish a workout with 100-200m easy, sometimes 300m. If it's been a mostly freestyle workout, I often do an IM (all the strokes) but use fins for the fly, just to stretch out. I usually don't stretch, as I almost never feel tight during/after swimming.

Bike: I finish long rides with an easy 15 minutes (home from industrial park where I train) and shorter ones with 5-10 minutes of easy spinning on trainer or stationary. Then some quick stretches--back, hamstrings, quads, calves--what usually tightens up afterward. Maybe 5-10 minutes max.

Run: Usually finish with about five minutes of walking. For speedwork (usually fartlek or tempo) the last 5-10 minutes or sometimes more is easy running. Then I walk a few minutes back home. Same 5-10 minutes of stretching as above.

I have issues with chronically tight glutes and hamstrings; occasionally my achilles will register complaints, too. It really helps to do some stretching out AFTER bike/run. By contrast, my upper body's really flexible, so I don't find stretching to be very useful.

There are those who swear by stretching, and those who think it is a waste of time and can lead to injury.  Based on my n=1 experience, I go with the former:

Swim:  easy 200, maybe mix the strokes a bit...sometimes reinforcing something I'm working on that day

Bike:  trainer 5-10 min CD as per workout dictates, outdoors maybe like 5 minutes spinning down before I finish

Run:  5 min walk outdoors or on tready

For every leg workout, I finish with about 5-7 minutes of stretching and the foam roller.

I think the amount of stretching needed varies with age. In my 20s, I rarely stretched. Now I need to stretch to avoid injury, especially from running.

Also have started stretching after swimming as a prehab, which hardly anyone does. Given the number of repetitive stress injuries from swimming, you'd think more people would stretch.

Thanks for all the input everyone! 

So by all of the comments I think I need to listen to my body as the need to stretch seems to be individual. 

For me- I think my 1/2 mile walk is good enough for a cool down. 

As far as stretching after run/bike I think I need to hit my calves (have had PF in past, do not want again) and my quads and hamstrings- I might spend 3-5 minutes on all three and then do a longer once a week.