How to savely upgrade software from ports?

[Rob Lahaye]

I'm having trouble how to savely upgrade software to newer version in the ports.
For example, "pkg_version -v | grep -v =" tells me:

linux_base-7.1_2   <   needs updating (port has 7.1_3)


I see two options, for this example:

1) simply install 7.1_3 *without* deleting 7.1_2.

2) delete with "-f" 7.1_2 and then install 7.1_3.
    (this is what the "pkg_version -c" output suggests).

Can someone tell me what are the pros and cons?
Is there another (safer) way of upgrading?

Thanks,
Rob.