I've been a PHP developer for many years now, with many tools under my belt; tools that I've either developed myself, or free-to-use solutions that I have learned to trust.
I looked into CodeIgniter recently, and discovered that they have many classes and helper routines to aid with development, yet saw nothing in the examples that I couldn't do just as easily with my own tools. Simple things like DB abstractions, Email helpers, etc. There was some interesting code relating to routes - mapping urls to the right controllers; but even that's not particularly difficult to code yourself if you've ever written an MVC style web app with pretty urls.
Even after looking through some of the other popular frameworks, I still see nothing that would be that much of a time-saver. Even looking at the forums, I see people struggling to get the tools to work for them. I do understand how they would be more useful for junior developers, since full system design skills take a while to understand and appreciate fully.
Yet, I'm often told that I should use an off-the-shelf framework to produce my solutions, but I still remain unconvinced. What's the real benefit to someone like myself? Am I just being elitist, or is this a common opinion?
Edit: Looking at some of the answers here, should I perhaps consider packaging up my toolset as its very own framework, writing some documentation and posting tutorials? If I'm hesitant to take on other's frameworks, would opening it up and getting more eyes on it help to improve my own skills/tools?
Frameworks have several advantages:
You don't have to write everything. In your case, this is less of a help because you have your own framework which you have accumulated over the years.
Frameworks provide standardized and tested ways of doing things. The more users there are of a given framework, the more edge cases that have been encountered and coded for. Your own code may, or may not, be battle hardened in the same way.
Others can be recruited onto a project with a standard framework and have access to the documentation, examples and experience with that framework. Your own snippets may or may not be fully documented or have examples of use... but isn't much chance that others are comfortable with them initially.
With regards to your idea of packaging up your own framework, the benefit of cleaning it up for public consumption can be larger than the benefit of getting others to use it.
The reason is simple: you will have to re-evaluate your assumptions about each component, how they fit together and how clear each piece is to understand. Once you publish your framework, your success will be strongly dependent on how easy it is to get up and running with.
Big wins with little effort are essential for adoption (those wins will encourage people to delve further into the framework). Ruby on Rails in an example of a framework that gives such big wins with little effort, and then has hidden layers of features that would have overwhelmed someone just getting started. (The question of the quality of RoR apps is not the point, the point is about adoption speed).
After people adopt a framework, it is about the ease of continued use. Little details like consistent parameter use patterns make all the difference here. If one class has many parameters on every method, while another has setters that are expected to be called before invoking methods, you will lose users because they can't get a "feel" for what is expected in a given case without resorting to the documents.
If both ease-of-adoption and ease-of-living-with issues are addressed properly, you only have to get lucky for people to adopt your framework. If those issues are not addressed properly, even an initial interest in the framework will wane quickly. The reason is that there are many frameworks: you will need to stand out to gain the advantages of having others using your kit (as they rightfully are as wary of your framework as you are of others).