Once I concluded a deal over the phone, sight unseen, for a particularly rare compass, then jumped in the truck and drove 800 miles to get the prize. Other acquisitions take years to conclude. I've spoken to individuals over a period of two or three years before concluding a sale. I know of instruments that I probably will purchase, but it may be years before the person or family decides to sell. Collectors must be patient.
Most collectors concentrate on a particular type of instrument or maker.
My collecting interests are much more rounded. While I prefer compasses, St. Louis makers and solar devices, I collect everything. The last few years I have concentrated more on makers that are not represented in the collection, and I've slowed my purchases of post-World War II instruments. My purpose in collecting instruments is to preserve them. I am not a dealer, and only occasionally trade instruments with other collectors.