It's a real dilemma. I've come across some really neat pieces and just flat didn't have the time and money to deal with them.
When I finally get the time and money the opportunity has passed.
Best/ worst one was a Farmall Super M i missed. Friend of a friend wanted to sell one cheap. I didn't have time to go look so turned it over to a buddy.
He went to look at it. "Cheap" meant free. Seems guy was moving and couldn't take it with him.