Updates or patches close discovered errors and security holes in a program and thus contribute to increased security.
It is important to apply patches promptly to minimize the time window in which the device is vulnerable.
Updates are provided for both the underlying operating system and programs installed on it. The most important thing is to keep the operating system and the browser(s) up to date. The easiest way to do this is to enable automatic updates. With browsers, this setting is usually already active by default.
If a software is no longer maintained, you should look for alternatives. For example, the Windows XP operating system no longer receives updates and should no longer be used from a security point of view.
Programs should be checked from time to time to ensure that they are still needed. If this is not the case, uninstall them so that you no longer have to check that they are up to date.