Trim Router question

Hi Folks, I have a question about the the trim again.
I want to router all the corners/edges on my exterior trim, do I do that before (on the bench piece by piece) I glue & screw it on the TD OR after its installed? My first guess is after it is installed, but I just want to make sure.
Clear as mud huh?
Thanks
Mk
I want to router all the corners/edges on my exterior trim, do I do that before (on the bench piece by piece) I glue & screw it on the TD OR after its installed? My first guess is after it is installed, but I just want to make sure.
Clear as mud huh?
Thanks

Mk