How many times can u visit a hifi store before it annoys the store if u plan on a purchase

Most audio equipment store operators possess extensive experience, allowing them to smell it out real buyers through intuition or conversation. Given that HIFI audio stores typically have relatively few customers, they highly value every visitor and each potential sales opportunity.

In my point of view, its highly depends on the customers themselves. Most male customers have a very clear understanding of what they want basic on what they have at home and wallet. Its totally fine that you sit there enjoy the music even with snacks but if you keep asking to switch the speaker or audio source etc, we will began to think “you gonna buy or what” 

Some audio  stores they are annoyed on one visit  if they think you can’t afford their stuff. Quintessence audio here at Morton Groove , ILLinois , Mike who is now successful audio store, He is super nice.Even when I can’t afford his stuff. He greet you with a smile, and invite you to listen of the system you choose.

the other day I got a long speech from the salesman about buying American is the right thing, buying anything else would be un-patriotic. Well, my ears don't hear where it was made, that's how limited they are....

And I never triggered this conversation, I just asked about 2 amps side by side.

Go as often as you want.  If you are friendly, and don't act as a pest--meaning you don't demand immediate service, you wait patiently for other customers to be served before you ask for any work they would have to do to set you up for a trial, etc.--you are not making much of a demand on their time.  Also, don't argue with them or try to prove them wrong; more than anything dealers don't like know-it-all customers.  I know dealers who actually like certain customers that don' buy much but bring to their day pleasant social interaction.  As mentioned above, bringing food treats helps too.

I agree with @jond 

during my college years I worked at a family owned hifi store, for our town some really excellent gear, Conrad Johnson, Phillips, Cary, Mission/Cyrus, Tannoy, Paradigm, Ariston, EV, NHT, NAD, Proton etc.. we had a small group that would come in in Saturday’s and make a visit. Always with some sort of doughnuts or pastry. We called the leaders of this band Siskel and Egghead. Fun guys, would buy some good stuff at times. (Like @larryi said the treats helped).  Great conversations, introductions of new music and passing the time when sales were slow.

My boss taught me that this was part of the gig, our local clutch of audio heads. They all have friends that they push our way with potential sales etc.. If the gawking didn’t interfere with business, no harm no foul. (He also told me that I could chop off their fingers if anyone pulled a grill cover off)