In Deco 8 your site changes are not "live" until you publish them. We changed out 7.5 template to 8 but did not publish the new site. We worked on the new site for a few weeks before going live. The down-side is that you can not really see exactly what the client will see until you actually publish the site. You can get very close but expect a few tweaks after you go live.
The following user(s) said Thank You: matt1, Artwork