Hello Dman 777,
As others have opined on your question. Go as often as you wish. You indicate that you’ve been to that store 3-4 times in the past year. That’s not very often but Imo there’s no “max” number of pre-purchase visits before you lay out some serious jack to purchase at that location. If you feel guilty about multiple visits without a purchase maybe buy an inexpensive accessory if they have something on hand during one of your looking/listening visits.