one of my LBS has a customer number scheme which lets the guy know how much you get off (useful as you don’t have to ask)
the other is smaller so a bit easier.
I take what is offered generally, not got a new frame for a while but would ask “What was included?” or see how much to add a headset or BB.
On parts will go with discount or fitting depending on how much of a hurry I am in.
Like most have said, it’s all about a customer relationship, I might not buy a whole bike but have probably got most of one over a couple of years and keep coming back. If I was to walk in off the street I would try to get a price but not push it.