This. Many times this.

The only time you would get into a full restoration project is when there is no possibility of buying restored version. So ultra-exotics and highly desirable classics valued at 500K and more.

Start with a car with a solid body, this is foundation of your car. It is also the most expensive repair to fix right, as to fix extensive rust everything has to be removed and then put back.

 

I got really lucky with the '70 I'm messing with, no-rust has been found so far (and it is pretty much stripped down at this point). The body mods have been challenging but at least they were known issues. I am sooo looking forward to being able to drive it.