I would say it depends on what you want with your phone. I have an 8 Gb 5c because I mainly use the phone for calls and messages. I installed apps I use regularly (15+) and ditch every app I don't like 100%. It helps being sorting out the best apps for what I need to do with it and to avoid a clutter from apps I rarely or never would use.
I don't game on the phone and don't use it for music, I don't work with Pages etc, read occasionally a PDF file and that's about it.
Photos are deleted once I uploaded them.
I realize I'm a light user and prefer my tablet, ereader and DSLR most of the times.
The 5c actually has 5.9 gb instead of 8, just checked and only used 1.5 gb.
Taptalk eats the most bites of all my apps.
So yes it can be enough but it depends on how you want to use your device