I also find it ironic when someone says "I haven't used an antivirus for 2 years and have never had a problem." Not all viruses throw up a message telling you that they are on the computer, in fact zombie viruses and key loggers are in their best interests to never let you know they are there. The only PCs where it MAY make sense not to run an antivirus are ones only ever used for gaming, which don't even get used for web-browsing or financial transactions and/or PCs that don't use an internet connection.
Your irony is flawed. As stated I use an on-demand scanner on rare occurrences. Why would its BitDefender based definitions keep me any more in the dark than your real-time av, when it comes to my 2 years clearance stamp of being av/free? Taking your logic, no-one really ever knows how free/clean they are.
Security choices are a personal preference based on many differing factors. I would never be so condescending and obtuse to tell people what they should or shouldn't do for security. I simply gave light to an option that I use and to date has been proven to work.
There are far more options for security that circumnavigate the requirement for a real-time a/v. Fact. Its personal knowledge, awareness and choice as to which one's you choose to use and implement.
Enjoy wearing your app manufactured tin foil hat if it makes you feel safer. But don't tell me to wear one too. Just as I in return do not tell you to take yours off.