Understanding heuristics is an important part of not only many engineering and other domains, but of life itself.
A heuristic is some rule or way of thinking which is known to be very helpful in solving problems. It may not necessarily be 100% accurate (it actually is not meant to be 100% accurate) but it is nonetheless very helpful in thinking. A rule of thumb is one of the well known heuristics.
It also applies to software. For instance, one of the well known ones is the KISS (“Keep It Simple Stupid”) rule in designing software.
There are also several heuristics when it comes to software testing like even a poor test is better than no test.
Similarly there are many other heuristics which are very useful to learn for software programmers.