We currently use UPPERCASE headers and titles quite a bit (probably too much) and are looking to adopt a consistent set of rules for when it makes sense to use...
Capitalize the first word
Capitalize Each Word.
I was hoping to find one simple generic rule that covers everything but haven't found it yet. I've found plenty of information regarding why I should never use uppercase ever because IT LOOKS TERRIBLE but that's not what this question is about.
My question specifically revolves around text for things like:
labels "Sort by:" or "Sort By:"
tooltips "Primary address" or "Primary Address"
buttons "Delete user", "Delete User", or "DELETE USER"
navigation "HOME" or "Home"
breadcrumbs "HOME > MANAGE GROUPS", "Home > Manage Groups", "Home > Manage groups"