PHP5 Exception Handling

Just bouncing a thought on you. I currently have a default exception handler setup. So far in the code, I throw an exception when something is wrong. i.e. Missing file, invalid argument, failed db connection etc... My thought was centering around if I still needed to use try/catch in the code, since I have a default exception handler. Normally, I would rethrow exceptions for it to bubble back up to the top, where its caught, and something useful done with the stack. So I removed all try/catch blocks, and its seems to be working as it should be. Just wondering if there may be an "gotchas" with this chain of thought. Or should I keep the try/catch blocks as it is??? Thanks