The necessity and benefit of stretching is a topic that is constantly under discussion. There are tons of studies out there, each proofing something else... Beneficial, not beneficial... What ever your opinion is, I am sure that you would find a study to "proof" it.
My personal opinion is, that when you do exercises that let your muscles contract, you have to stretch out that muscle again in order to stay limber and prevent injury and/or pain.
When it comes to stretching, I am trying to be much more diligent, because I know how fast it can get painful for me, if I skip it too often.
So these are my stretches that I do after finishing up biking or running, before I even go back into the house:
As alternative to this move, you can also stand on a step on the balls of your feet and then push your one heel down and then the other.
This is the same stretch. One time standing and then one time sitting. Reaching to your foot with the opposite hand will give this stretch extra oomph.
The last picture looks like a lunge, but is different. You will have a slight ankle in your back leg and then push your hip forwards.
A LITTLE BIT OF EVERYTHING