when migrating to a new mac will old useless files move as well

If you want to migrate one user login or all of them, that’s selected at Setup Assistant.

You’ll see those other users and other logins in addition to the “Michael Cavanna” user that’s shown here:

… Move your content to a new Mac - Apple Support

If you have those other user logins present now and no longer want them, you can use System Preferences > Users & Groups to remove them withoutnre-migrating. Or can log in and clean them out manually, of course. I’d suggest keeping or having a “backup” admin user around as resolving a problem with the sole admin login (forgetting the password or otherwise) gets ugly.

Files in user directories do move. Some files and some data does get rebuilt. Some files known no longer needed gets dropped. Incompatible apps can get relegated to archives. Do consecutive migrations accrete files? Yes.

Mr. Hoffman:

I just inadvertently learned that lesson about consecutive migrations accreting files. My question now is is there a way to wipe my new MacBook Pro clean and then just migrate my one profile versus the 5 that I previously migrated.

i just want to start over on my new machine. Is there a simple way to do that? Thanks for your help and wisdom.