Given time and training, a human can do surprisingly well at designing data structures and algorithms.
Given time and training, a human will still do surprisingly poorly at maintaining data structures and executing algorithms.
Humans should do the creative work. They should leave the bookkeeping to computers. That is the essence of programming.
If it costs more to automate a process than to perform it manually every time, automating it may be a poor business decision. Beware the false economy, however. A once-and-done task is a very rare creature, and frustrated workers can cost much more than a few "wasted" hours.
Here are a few tasks that should be automated, but are often done manually (or not at all).
- Checking that code meets style guidelines. Most languages have tools for this. Add the one(s) you need to your version control hooks, and integrate them into your editor. If your editor doesn't support external analysis tools, switch to a better editor.
- Making a project's distributables. Each of them should be buildable in one step. They should be built regularly, to verify the build process has not been broken. There are tools for this, too.
- Installing a distributable should be automated (a human may need to answer a question or two, but configurable defaults are usually better).
- If backwards compatibility matters (and it usually does), it should be tested automatically.