Don't be too quick to diss the meds that can help.
It's not really a "given" that all men work all the time. Other meds, medical conditions, and age all are factors in performance. And, those changes start slowly and build over time. It's not like you wake up one morning and need meds to help with ED all the time.
I would mention it to your doctor next time you have a physical. He might have more insight than what you will find online in a forum like this.