I've heard a lot about cms's like drupal, joomla, and wordpress. I've always hand-coded most of my PHP and HTML and done fine. What are the pros and cons of using a cms?
The pros of using a content management solution are:
CMS to me is really for a website with a large amount of ever changing content that is managed by many people. The farther you get away from a large content management user base and constantly changing data the less likely it will have value. If your site needs to be agile in that its format and layout is always changing and a great deal of your content fits into a specific format that needs more fields that what a CMS has to offer then CMS may not be the best fit.
I am a little in the same position as you - cranking out my own pages in AJAX/PHP/HTML/MYSQL, and looking at CMSes.
CMS seems very attractive and the advantages are obvious, but so far I have found they also represent a significant investment in study.
Installing a CMS like Joomla is easy as pie, you can find templates and build something that looks good in minutes, and easily add articles and pictures and stuff BUT if you are going to customize anything, or if you need something to work in some specific way, you will need to learn how the CMS works behind the scenes, how to write plugins, how to create templates...
I made a basic install of Joomla on my testing server. 3,918 files, 712 folders and 36 db tables. Figuring out what does what and how is bound to take some time.
That said, making templates doesn't seem too difficult and you can add features in minutes where it would take some serious work otherwise. For instance, I just went and added a blog component to my test installation. It took about 30 minutes to find, install, configure and post the first entry. Making your own blog engine and integrating it into your website could easily take weeks.
If you are willing to surrender the level of control you are used to (at least at the beginning) and to learn how to do stuff in whatever CMS you choose, a CMS should be great.
Personally, I am looking into using wordpress as a CMS, but until I feel comfortable with it to do whatever I want, I stick to coding by hand.
People write books and build careers out of selling answers to that question. You're not going to get a proper, relevant answer here.
Maybe if you provided some information about what the applications you write do then at least there would be a chance that the answers might be relevant to the question. The term Content Management System encompasses a huge variety of software.
Stop and think about how you could be better and more productive as a developer. Make a list of things which are difficult, you spend too much time on, or are just plain boring. Maybe there is a CMS which might alleviate these. But without knowing what the problem you need to solve is, we can't provide a solution.