This question is for the guys who take it becasue they have to, not because they want to have an erection for an hour.
If you can't get an erection...where is the need to have sex, I always thought the first one was a signal that you needed to do the second one?

I don't take Viagra because I haven't needed it yet, but I'm 42 and my response times are getting longer.

Put simply, a desirable woman is desirable whether I'm erect or not.  For me, at least, the thought that I'd like to have sex with a woman usually occurs BEFORE I get the erection, not after.

When I was in my early 20s, I was basically a hormone with feet, and spent most of my time erect anyhow, so it was more a question of where I was going to aim the thing.  Now that I'm older and presumably wiser, I find my self desiring a woman for her intellect, her sense of humor, her creativity, her communications skills and her compassion.  I still like to look at women with pert breasts and full hips, but attraction and desire are more complicated than just her looks and I am thinking about making love to her long before I have to worry about aiming the thing.

So, if I were to venture a guess as to why a guy might need Viagra...I'd say it's because he's seen things in his lady that make him want her even before the time than erection becomes a factor.

Yoda