You know you're an audiophile if--

you spend an excessive amount of time, listening to music, buying and selling components, and talking about the hobby.

what constitutes "excessive" is determined by a panel of psychiatrists or psychologists.

the hobby can be a disease if one neglects other important activities of living.

If you own a set of stax cans and they are more expensive than your car. :)

If your friend or family member ( mostly much juniors in age ) casually ask you to help them with a tip to improve their 2ch audio system set up ( with a very modest budget in mind ) and you keep explaining to him/her all about the sound quality and the equipments matching , till the person who asked gets emmensely bored and almost regrets asking you.

12-24-12: Radni
If your friend or family member ( mostly much juniors in age ) casually ask you to help them with a tip to improve their 2ch audio system set up ( with a very modest budget in mind ) and you keep explaining to him/her all about the sound quality and the equipments matching , till the person who asked gets emmensely bored and almost regrets asking you.

No, that makes you an ahole.

If your wife has no trunk for groceries, every room in the house has a stereo (including bathroom's), and I have a dedicated room just for audio! Not to mention I get some of my best sleep with bands like Tool (heavy metal) playing at 120db in my room.

Even my cat climbs into the ports of my sub boxes and takes a nap..... with music at volume. My son is 10 yrs old and constantly changes the setup I gave him for his room. My 5 yr old daughter, huh, I don't even want to get into that.

Or maybe it's because I have eight 12" subs, four 8" subs, and six 6" subs on bass alone. Add to that a total of eleven 6"mid-bass/mid range drivers and eleven tweeters. Four amps (three for bass alone), a custom built room with walls that are held in compression (anti-vibration), bracing on the ceiling, a concrete floor, dedicated power supply, ample diffusion, and I don't know what else to mention. Oh! Neighbors that don't complain no matter the hour!