from http://maven.apache.org/guides/getting-started/maven-in-five-minutes.html
package: take the compiled code and package it in its distributable
format, such as a JAR.
install: install the package into the local repository, for use as a
dependency in other projects locally
So the answer to your question is, it depends on whether you want it in installed into your local repo. Install will also run package because it’s higher up in the goal phase stack.