The question, "Can you have HIV for 20 years and not know?" is a serious one. While medical advancements have greatly improved detection and treatment, the answer, unfortunately, is yes, *it's possible*, although increasingly less likely.
HIV can remain asymptomatic (without noticeable symptoms) for many years, sometimes a decade or even longer. During this 'clinical latency' period, the virus is still active and damaging the immune system, but the individual may feel perfectly healthy and not suspect anything is wrong. This is why regular HIV testing, especially for those at higher risk, is crucial.
Why the risk is decreasing? Firstly, testing is more readily available and encouraged. Secondly, even when asymptomatic, opportunistic infections are less common with modern healthcare. However, relying on symptoms alone is a dangerous game. Early detection and treatment are vital to preventing the virus from progressing to AIDS and ensuring a long, healthy life.
Get tested. Know your status. Protect yourself and others.