If I change my permalink structure, is there is a nice way to handle when people/bots go to the old structure?
I presume I can add use .htaccess and write a rule to redirect based on a 301 but is it possible in my case?
I currently have site.com/%year%/%month%/%day%/%postname% and I will just want site.com/%category%/%postname%
Dean’s Permalink Migration has always worked for me. Install it before you change your permalinks.
For people, you can try Smart 404.
I would recommend two plugins for this: either Redirection – a good way to manage your changed urls / permalinks, and 404 Redirected, which is good for logging and manually fixing permalink errors.
You can typically perform the 301/302 redirect in the functions.php file of your theme.
Here is one of many references you can find – http://perishablepress.com/permanent-301-redirect-via-php-or-htaccess/