Tried reacting to the CreatedUrlSegment event?

Set up in initializable module.. 

public void Initialize(InitializationEngine context)
{
UrlSegment.CreatedUrlSegment += UrlSegmentOnCreatedUrlSegment;
}

private void UrlSegmentOnCreatedUrlSegment(
object sender, UrlSegmentEventArgs urlSegmentEventArgs)
{
var segment = urlSegmentEventArgs.RoutingSegment.RouteSegment;
...kill hyphens, shorten the urlsegment, to lower etc...
}

If that doesn't work let me know and I'll check some source code where I solved that one a few years ago.. 

Thanks for the advice. Unfortunatly if im not mistaken the CreatedUrlSegment event is only fired when the segment is created the first time. I also need to act on urlsegment changes and if the url segement of the page is changed the event is not fired. 

Please check if you can find anything or if you have any other idea. 

Tahnks for the help!

The evicting of cache entries for url segments are also triggered by events from IContentEvents. It appears that your event handler is registered before the event handler that evicts cache entries. To ensure your cache handler is registered after the one eveicting from cache a suggestion is to hook up your eventhandler inside an IInitializableModule.Initialize method that has a ModuleDependency attribute set to EPiServer.Web.InitializationModule.

...or move logic to publishing event and check the updated item vs the one that already exist

private void InstancePublishingPage(object sender, PageEventArgs e)
{

var contentLoader = ServiceLocator.Current.GetInstance<IContentLoader>();
var contentReference = new ContentReference(e.Page.ContentLink.ID);
if (!ContentReference.IsNullOrEmpty(contentReference))
{
var languageSelector = new LanguageSelector(e.Page.LanguageID);
var page = contentLoader.Get<PageData>(contentReference, languageSelector);
if (page != null && page.URLSegment != e.Page.URLSegment)
{
var pages = _contentService.GetDescendents(page.PageLink, true, languageSelector);

...

...or install SEO Manager that will automatically create 301s if you do something like that. :)

Thanks alot Johan that seems to work! 

You are right Daniel this should hopefully never happen but you never know with editors :)

More likely they will move stuff around in the tree which will be the same problem from a SEO perspective.