Same ad format, same page, new unit?

Should I just use the same code at both the top and the bottom of the page?

[proboscis]

For example, if I have a 728 leaderboard at the top of the page and I want to have a 728 leaderboard at the bottom of the page, then should I just use the same code for both?

Or is there some advantage to creating a second ad, other than creating a separate channel?

I'm not using any channels on this site.

Thanks!

[netmeg]

If you're not using channels, then you might as well use the same code.

But if you're not using channels, you won't know which one does better.

[proboscis]

Thanks netmeg, I thought so but I wasn't sure if it was necessary or not.