As @Dannydet kindly said, some apps won't use more space than what they had when they were originally installed.
Other apps will grow as they're used, consuming space as they save and update their files/databases.
Each update that you're seeing for an app only causes it to grow if there are:
1) new files not previously present/installed
2) old files that are updated/replaced are larger than the ones before
These files include all of the components of your app (i.e., their code, resources, images, etc.--whatever you see inside the .apk (.zip) file.
Additionally, Google continues to make changes to how large an update to an app actually is:
which references this page:
So, you can't rely on the size of an app update to tell you how much bigger (or smaller in some cases) your install app footprint is.
Does the installed app takes up more space after it each update?
