My main drivers are IBM Model F 122-key terminal keyboards.
I have the most pristine specimen in deep storage, and alternate between a "naked" one without a case and a more typical cased one, both with my "ANSI-mod" to approximate a modern layout.
Whenever I get a "new" (almost always used, and usually cleaned and refurbished) (usually something on the order of once a week, although it might be 3 weeks) keyboard, then I rotate it in for somewhere between a couple of hours and a couple of days, and really get a feel for it.
So far, nothing has displaced my true love, but I keep the window of possibility open.
Also, since I usually sell the ones that I don't keep, I feel like I need a good sense of what they are and how to describe them.