You should really update the extras packages from time to time as the update may contain bug and performance fix, other than features update.

However, you'd really want to hold back some package until it's more stable, if you don't want to reflash that frequent.

Say I hold the kernel power to v46, as v47 is a big leap since its previous version.

To hold the update of a package, you can:

The exact package name can be found by dpkg --get-selections.