Naturally, if you know in advance that you're going to be working with both 4x5 and 8x10, then it makes a lot of sense to buy kit with both formats in mind.

However, in my journey, it was never quite so obvious and what makes it worse, and in no small part to this forum, I've gone head-first down the "historic lens' rabbit-hole, with the unexpected consequence of perhaps never wishing to use a 'modern' piece of glass to take a photograph ever again...