It kind of depends on what you mean by an IDE. A good language sensitive editor (LSE) is a must and frankly I use Geany like you. Mostly I do Bash and Python stuff these days, but have also done a bunch of C programming in Visual Studio. I also sometimes use a Python IDE (Spyder) for very specific things.
Where I have never liked IDEs is building and packaging code. Give me GNU Make or another tool please. IDEs just make things complicated. Debugging... I do not know. Graphical debugger is good, not sure it has to be in an IDE but maybe it helps. The other place I like IDEs is integration of other tools like static code checkers. The code navigation is really helpful too (an LSE at another level especially with many modules). The thing I do not like is IDEs are often just too much. So I tend to start with Geany, and go into an IDE if it makes sense, like for a bigger project or something or some feature like static code checking.
The thing I do recommend though is version control. Probably these days git, but there are things I both like and dislike about git. Another good tool is meld (or some other diff tool). The there are the standard "diff" and "patch" commands.