I love the way they pick and choose among errors, too. No cobra glass-reflection in Raiders of the Lost Ark, but they leave in the truck's roof-rack falling off during the chase, and then being back in place. Or the clasps on the book coming open when Jones slams it down on the library table, only to be shown unclasping them manually in the next shot.
If your mission is to fix the errors, you as the filmmaker should be familiar enough with the piece to know where every error is ... and then spend the money to fix them. Don't just fix the easy ones. Otherwise, leave your film alone ... it's a piece of history if, like Raiders or Star Wars, it made a huge impact when first released - warts and all.
.