Should I reinstall any part of Macports when upgrading XCode?

This page claims that both XCode and MacPorts should be reinstalled whenever a major system change occurs (e.g. upgrading version of OS from 10.8 to 10.9). I have done this before when upgrading from OS X 10.9 to 10.10 (of course, XCode and many other things got updated at the same time). It took a while to migrate MacPorts afterward, but it allowed a port to install that wasn't installing otherwise.

I know that MacPorts by default uses XCode. Should I reinstall/migrate my MacPorts according to that page whenever I upgrade XCode, too?

Follow-up question:

Are there other times When is it a good practice to reinstall/migrate my ports? I'd like my system to be running lean, mean and clean. :-)