In Germany there been big problems with the German CAA (what ever their called) insisting on the Cessna SID being implemented.
At great expense to aircraft owners.
Were as the UK CAA have said only AD,s and SB are mandatory..
Now this rule change has meant they can tell their CAMO to disregard.
There's also the issue of life,ed parts.
And engine TBO,s were some countries in Europe don't allow extensions at all.