What was your experience with changing site url's?

[KentH]

I work with a company that is about to move to a new platform.

Because the category and page structure is different every almost every url but the home page will need to be 301 redirected. I know how to do this and am pretty sure I will find and fix 99% ahead of time and not have too many 404's showing up in webmaster tools to clean up.

My question is has anyone who is reading this post had to do this before and what was your experience with organic traffic after you made the switch. I am predicting that even if I successfully redirected 100% of the url's there would be some loss for a couple of months just due to the fact that we are making a major change. My bosses are asking if there will be any loss and I need to tell them what to expect.

[max.favilli]

Is the content staying the same?

If the content is staying the same, and just the url structure is changing, and if the new url structure is not depriving the url of the relevant keyword for the page content...

If all these conditions are satisfied, in my experience moving few websites, replacing only the url structure (theoretically improving it), nothing changed, I mean I didn't experience any traffic being lost in GWT or analytics, I didn't even notice any unusual fluctuation.

Of course keep in minds the traffic is moving, from the old urls to the new ones, so depending on your report and your new url structure you will see it in different places.

[RyanPurkey]

Hi Kent. This can vary pretty substantially based on a number of factors, but losing organic traffic for a a couple of months would be on the high end of delays and cause for concern towards the tail end of that time. There's a nice migration guide here from 2012 that's still relevant: http://moz.com/blog/web-site-migration-guide-tips-for-seos.  Mostly it comes down to solid planning and good promotion of the new site address to really help the process along.  Cheers!