Custom Plugins vs. your theme's functions.php file

It is standard practice for us to create custom plugins for our clients’ WordPress sites. We go the custom route (rather than plopping them into the functions.php file) for 3 reasons:

1. Portability – you can change themes and not lose the custom functionality – plus you can switch to a default theme to debug problems and not break everything
2. Bloat – functions.php files can quickly become unwieldily
3. One slip-up in functions.php and your site greets users with the White Screen of Death.

wplift has a great write-up on when to use functions.php (rarely) and when you should create a custom plugin (always).

So there is a little insight into our development approach to adding custom functionality to your site.