gulp: Watch is very slow to recognize file modifications

This seems to be a common problem for me, but I haven’t been able to find any issues about posted about it. Maybe I’m just doing something wrong.

When I’m developing, it frequently takes the watch task 5-15 seconds just to recognize that a file was modified. Once the task actually starts, everything execute quickly, but the problem is triggering the watch task so it notices my file modifications. This makes development much slower than manually calling a particular task. Here’s my very simple watch task:

gulp.task('less', function() {
    return gulp.src(paths.less)
        .pipe(gulpless())
        .pipe(gulp.dest('./public/css/tmp'));
});

gulp.task('watch', function() {
    gulp.watch(paths.less, ['less']);
});

Is this normal behavior? If so, is there anything I can do to speed up the file modification recognition? If not, how can I benchmark what’s taking so long?