For one reason or another, there always seem to have been skulls around the house. Cattle skulls (since we were graziers), bird and wallaby skulls in the Interesting Things Basket on top of the microwave (this collection, and its eventual demise, made it into Flyaway). Then at college there was an anatomical model that would show up clothed and posed in dorm rooms from time to time. After that, my housemate was a vet student and kept a reference dog skull on top of the television (this, combined with preg-testing gloves draped over the back of a door, explained the awkward atmosphere during a visit payed by some police after my car was stolen).
And then, one day, I was skull-less (or rather, all the skulls in the house were in active daily use), at which point I realised how much skulls show up in my line of work — and how useful reference really is, even for my typically very stylised approach.
There are plenty of references online, of course, and handy adjustable skeleton apps (I think I used one for the Illustration Master Class paintings), but they aren’t the same as being able to turn an example to the light, or glance across idly to confirm a suspicion about particular bones — and a too-adjustable, over-detailed option (especially one which, as in an image search, shows up at the scale I’m working at) tends to make me want to copy it exactly, which isn’t at all my style. In art as in prose, I prefer to hit a point somewhere between allusion and plausible deniability.
I bought a replica anatomy chart, but my then-housemate (not a vet student) disapproved of it hanging in the common areas, so now it gives my room a far more Gothic aura than it would otherwise have. I used a tiny vodka bottle for a while, in a pinch, but it had its drawbacks.
Finally I bought Mortimer, who now lurks on top of a bookcase behind my desk and features — more or less — in many, many illustrations.
(There are also a few skeletons up in the Halloween collection on Redbubble.)
And since the era of Zoom, it comes in handy for other things, too.