We've been renovating for 6 months and only just found out where our plumber has been buying all our stuff.
This is one of those things that feels obvious in hindsight but genuinely didn't occur to me until halfway through the project.
We've been doing a full kitchen and bathroom renovation. Our plumber kept turning up with well-priced, decent quality gear: fixtures, tapware, that kind of thing, and I finally asked him where he sources it. I had heard of it as a plumbing supply company and didn't pursue it further.
Turns out they also do a full range of kitchen appliances, cooktops, ovens, rangehoods, dishwashers, the lot, available to regular consumers, not just trade. walked into the showroom and had an actual conversation with someone who knew what they were talking about, rather than a commission-based sales floor person trying to move floor stock.
The rangehood advice alone was worth the visit. I was about to buy something undersized for our cooktop, and apparently, this is extremely common, and they talked me out of it before I wasted the money.
But just because there may be other places that offer better service and prices, it doesn't mean that you should ignore what this showroom can do for you. I had been sticking with the big box stores through sheer habit.