A couple of months ago I was contracted to work on a project for a large UK organisation that provides accreditation for university, and other, further education courses of a certain type. The site had already been mostly designed and built so I had no say in its overall structure. Suffice to say: I wouldn't have done it like that.
Still, we play the hand we're dealt.
The nature of the project meant that the applicant had to fill in absolutely massive forms and provide huge amounts of evidence to show how their course delivered to the standards required for accreditation. But the form could not be submitted for review until it was complete. But the forms are so huge that nobody is going to be able to fill them in in one sitting. In some cases it's expected it would take weeks.
The original developers had decided (sensibly) to use the Content Complete module, which is a watered-down version of making a field "required" - you specify which fields need to be complete and then you can check every time the form is saved. Which was all well and good except for one tiny thing: these forms used Field Collections and Content Complete cannot cope with Field Collections.
The first task on my list was: get Content Complete working with the Field Collections.
I laughed til I stopped.
I did have a look but Content Complete is structurally incapable of handling Field Collections without a major rewrite. Anyway it was worse than that because I had to create new forms which required linking to other entities (via Entity Reference) and they needed to be checked for being complete as well.
Now there was a discussion in the Content Complete issue queue about developing a new version called Entity Complete. However the ideas were overly complex, wanted to carry on using the same interface (which I don't like), no actual work had been done, and the discussion had dried up months ago. Clearly it wasn't happening.
So I had a choice, somehow fix Content Complete, or start again and write the Entity Complete module from scratch myself. So that's what I did. Essentially it intercepts just two hooks to achieve the required result but there are plugins for specialised field types. And lots of frills.
You can find the module itself here. You'll notice it's called Field Complete instead of Entity Complete because someone had already grabbed the 'ec' short title.
And there is lots of lovely documentation with many pictures here.