Take a pro-active approach to the heel problem. Apply patches before you see any trouble, even when they're new before you wear them at all. Use contact cement or an equivalent with material from all those spare wader patch kits you have around. As others have said, wear a sock over the neo feet as some added protection. I use Simms' 'Wet Wading Sock' that any Simms dealer should have for $15. They're thin but tough and last a couple years for me.
Mark