You are unlikely, especially in these times, to find one supplier who can provide everything that you need.
Over the years, I must have used nearly ten different suppliers, for different items. Some specialise, such as just cutting tools, or Taps and Dies, in other cares, it may be that the particular item is only stocked by that particular vendor.
In other cases, you may have a choice of three or four (What is basically the same machine may be offered by four or mor importers, but in a different package and colour scheme. In some cases the device that you want is not available for your machine, but one for another can be adapted.
(In my case a Vertical Slide for a Sieg SC6 was fitted to an Engineers Tool Room BL12-24 with a simple adaptor )
Materials can sometimes be obtained locally, and possibly more cheaply in a large quantity, than by mail order.
It may be, that over the years, for various reasons, (service, technical back up, quality etc ) you build a better relationship with one supplier than another, and they supply most but not all of your needs.
Having bought machines and accessories from four or five suppliers, some are more likely to get repeat business than others.
You have to match the horse to the course, and be prepared to be flexible..
Howard.