They DO matter; and that means they can be as damaging under misuse, as helpful when used sensibly.

Changing the Hx attributes with css makes no difference; what matters is the numbers of Hx tags, and the way they are used; there's plenty of advice on using correctly; eg only one H1 per page, use others in a heirarchy.

The joy of NOT using css is that the appearance of the page will warn you if you've overdone it. The page will look plain old fashioned stupid. So if in doubt check without css.

Use css with HX to get the best page design. If H1=14 and H2=14, for example, then clearly you are missing something.

If there's no hierarchy, then there's trouble brewing.

I hope that helps.

Yep it did. :) Thanks.

I completely understand HOW to use them correctly on the pages, however, I have heard that changing the font size of them via CSS may be damaging because the search engines see the Hx tags and think "Ok, thats a header, but wait... why did he change the size of the header? He's trying to trick me! Let's hurt his rank."

Any truth to this?

I've heard it too, but I've seen zero evidence, and don't believe it.

I have heard tales of people doing crazy things with, Hx and CSS then getting problems ... but on cross examination, it turns out they were usually doing other many high risk activities known to attract SE action.

In my experience, overdoing it is the danger, esp H1 tags.

Yep, I completely agree. I usually limit my use of Hx tags on a page. I was mainly just worried about changing their size in stylesheets.

h1 {
font-size: 14px;
}

Do search engines see that as cheating? Hence not ranking so high? Cmon, lets face it. A regular H1 tag is HUGE and ugly.

I've heard it too, but I've seen zero evidence, and don't believe it.