I've really just begun to learn OOP. I started about a year ago and have written probably 15,000 lines of it. But I wrote it all with hardly any experience looking at other people's OOP.
Most of my class functions return a value or make a change to the class properties and return true/false. Some of the ones that return a value also save that value into a class property (after first checking if the class property is already set, which can avoid a database call).
Now I'm doing a lot of digging in Magento/Zend and I notice a lot of their class methods return "$this". As I understand it, unlike in regular functions, class methods that return $this act by reference not by value, so that you get back the same object you started with rather than a copy.
$this something that I should be doing much more of? Does it make the code easier to maintain and use? Is returning
$this necessary in order to chain class methods?