I have worked with three different bookbinders a fair amount over the years, and they rebacked or rebound dozens of books in my collection which were in bad shape.
I just acquired my first incunabulum, a 1483 volume in Latin printed in Nuremberg by Anton Koberger. It's a nice copy, internally, but it is in a later binding which has seen better days, a very plain binding of black paste paper boards over a black cloth spine.
I have a couple of binders I've worked with quite a bit over the years. Were this a later volume, I wouldn't hesitate to choose a simple, attractive style for the rebind. But this is the most I've ever spent on a single book (about $4,000), and I'm pausing before I do anything.
As a general principle, would you treat an incunabulum like this any differently than any other older volume - from the 16th or 17th century, for example - for binding purposes? Naturally, I assume a nice full leather rebind would improve the value to a buyer, given its rather homely current appearance. This volume is about 8 1/4" x 11 7/8" tall x 1/2" thick. It has nice wide margins, and should rebind nicely.
Any advice? Is there any particular style or approach you would favor over others? I've looked around quite a bit, but haven't seen too much on point, one way or the other, so perhaps I'm overthinking it . . . .