I've pretty much always built my own blogging engine. In fact, I've spent more time building blogging engines than I've ever spent actually writing blog posts. The previous version of marcyes.com was built around the end of 2006, a few months after finishing my Computer Science degree, while I was waiting to start my first real job as a Patent Examiner at the PTO.
I was actually quite proud of that little blogging engine, it had all the common bloggy things of the day (trackbacks, comments, and rss) and a few others that no other blogging solutions had at the time (ajaxy image file management, expanding text boxes, SQLite backend, and link caching).
But over the last few years I've realized just how long in the tooth my blog had become (I hadn't touched the code in years, and it also hadn't had a design refresh), lots of whiz-bang features no longer worked quite right due to newer browser incompatibilities (but it worked in ie6) and just plain newer versions of everything. Also, I used my blog for a lot of non-blog things that I eventually replaced with other, better services. For example, my blog would cache links locally and make them searchable (using Lucene), but so could Evernote and it was available on my phone. It also turns out I don't blog much, so I don't have a lot of readers, and therefore I don't have a lot of comments (good thing I added all that comment moderation stuff), or rss subscribers, so those features got built, but never really got used.
Since my blog no longer worked quite right, and was way outdated aesthetically, I mostly stopped blogging altogether until I could update the software (the last public post was May 7, 2012, and the last private post was on March 12, 2013). Well, I've finally sat down and built a new blogging engine and gave the design a new coat of pain (with custom fonts and everything) :)
Why didn't I just use Wordpress?
I love Wordpress, but I think this answer from Marco Arment pretty much sums up my feelings on the matter also:
I'm a programmer, it's what I do.
I like building things, it's not only what I do, it's what I enjoy doing. Also, I like things a certain way and all the other blogging engines didn't do things exactly how I wanted to do them, so I wrote one that did do things exactly how I wanted to do them. Hopefully, I'll even blog a little more now.