I am 61 years young and I was having occasional problems with maintaining a firm erection, especially when tired or distracted. A friend gave me a 100mg Viagra tab. I split it in half...Whoa! Like one of the other guys said....what a boner. My wife loved it. Thirty minutes after I shot off, it was up again. Damn near wore both of us out.
So....I have a Dr friend. He checked me out and wrote me a prescription for 100 mg Viagra and 20 mg Cialis. I only need about 1/4 pill (about 25mg)of Viagra or less to have a really nice hardon that is predictable and the effects last about 2 hours. The Cialis keeps things active, with the appropriate sexual stimulation, for 48-36 hours for me. Not the crazy hard boners that Viagra gives....but about 90% as hard for a much longer period.
Side effects.....Headache and sinus stuffiness with both. Side effects more noticeable with Viagra, but as noted elsewhere easily managed with ibuprophen and, though I have never had to, a nasal decongestant.
These two drugs work as advertised and certainly have been a real boost for me.