This is just one person and one example (YMMV), but when I first built my current modest home project studio some ten years ago or so, I started right out of the gate with two pairs of monitors., My 824s, which I have set up in a typical nearfield configuration, and a pair of Klipsch Kg0.5 consumer bookshelf speakers which I have mounted on projecting wall brackets up on the wall behind my desk, that I have hooked up to my Denon stereo receiver. The idea was I could compare my mixes on the 824s to a "typical"-sounding consumer setup.
The reality turned out to be that it only took a couple of months before I stopped referencing my mixes on the Klipschs for the simple reason that it only took that long for me to "learn" the translation between the two, and learn that even though the Klipschs sound quite different from the Mackies, that the translation was really not all that large of a leap; I knew that if they sounded such and such a way on the Mackies that they sounded "right" on the Klipschs. So I just started mixing that way and it all seems to come out OK now (and on earbuds too, FTM).
Translation to car stereo remains a bit of a problem, largely because there is a huge translation difference there, and largely because, when in analytical/critical listening mode, car stereos generally suck no matter what one pumps through them.
G.