Okay Teresa, now you're talking! Still need to know "how big" so that we might do a better job replying.
I have hosted my own moodle for around 7 years. I have about 15 courses per year, and about 400-500 students per year. I started hosting my moodle on a $5US/month hosted server. When this became too small, I moved to a VPS (GoDaddy) and I pay around $200US/year for this. I think I could easily handle twice my course/student load, if needed. By having a VPS with a hosting company, I don't have to worry about all of the network hardware issues.
I am pretty good with technology, don't mind learning new things (like Linux), and my Moodle has performed solidly for me. Having a great LMS available to myself, which my colleagues don't have, gives me an (unfair) advantage educating my students.
Yes, I really like the freedom of being my own administrator and deciding myself what features I want and don't want. If I were to leave this to an IT department they would probably compromise my capabilities.
Some of how hard things are depends upon your own personal demands for features. I run a pretty standard moodle with only 3 plugins. I also run one of the basic themes (MORE) and customize this only with CSS code. I never touch any of the core moodle code. I also use self-enrollment for students, which has always worked very well.
However, if I were going to do this for a school with 5,000 students, I would probably switch to a third party provider.
Incidentally, I am a professor and not a network support person. As I professor, I do all of this on my own.