G'day tobyink,

Your usage seems to align with mine. For single loops, I don't generally supply a label. For nested loops, I'll generally give all loops a label; although, if I'm not using next, last, etc. I'll probably omit the labels, e.g. for processing all cells in a grid:

for my $row (1 .. $row_count) {
    for my $col (1 .. $col_count) {
        # process cell at row $row and column $col
    }
}
[download]

Not really related to loops but years ago, when working with junior programmers who didn't fully understand lexically scoped pragmata, I'd use labels to document anonymous blocks; usually something overt, such as:

SUBROUTINE_REDEFINITION_BLOCK: {
    no warnings 'redefine';
    sub subname { ... }
}
[download]

This followed several instances where braces delimiting anonymous blocks had been removed because "they looked like superfluous code".