20 years ago, I would not have believed PE can work.
Because only muscles can be developped by means of excercises, they said before.
But I trained again a bit athletics, throwing javeline and discus, and for improving you get to train short sprints; there, I had regularly periostitis, i.e. legbones inflammations, due to microwounds inside my legbones because of the repeated shocks,
and my bones became clearly thicker.
Of course, if you stop totally training, you loose your gains.
But this is true for brain, muscles, know-how, and so more in life.
So, when I discovered lpsg, and read Big Al's adviced, I believed what he said, and tried a bit.
It works more or less, according to your body and your training (beware of not overtraining).
Now, this is also a matter of motivation. Mine is not high, because I don't hope "I will lay girls" with that. My wife is not a size queen, even if she enjoys (not ofen enough).
If you are young and have no children, your availibility is much higher than mine, with four children.
A motivation can be that your girl enjoys making love with you but does not really pay attention to your dick as a nicest tool and important part of yourself, so you find in PE an occaion of fondling your penis as nobody can do it.
As Big Al says, try, and you will go on maintaining if you are satisfied.