Depends on whether you are doing it in a smart and efficient manner, or just blindly running -a every week.
Just because there is an update in the ports tree, doesn't mean you have to install it right away.
My home desktop/server hybrid has over 1000 ports installed, with a couple of hundred updates available every week, but I spend less than an hour a week doing port upgrades. Unless there's a major jump in version number, an known security issue shown via portaudit, or a specific feature that I really need ... I don't update installed apps.
Blindly running
portupgrade -a every week, especially with --batch, is just asking for trouble, corrupted installs, and issues.