Super Newb wrote:
I've never varnished my models. Should I do that once I finish my gesso primed models? Is gesso really noticeably less durable?
Gesso isn't much (if any) less durable, but a varnish is always recommended no matter what primer and paint you use. It's a very quick step and is really the only way to make sure that your paintjobs survive extended tabletop use. A spray on gloss coat followed by a matte coat is best, but at a minimum, 2 layers of brush on matte varnish (if you've got nowhere to spray) will go a long way toward preserving your minis.
My minis are dipped (a liquid polyurethane and stain mix) which is even tougher than a gloss spray coat and then I give them a coat or two of matte to kill the shine.