The Software Has Packages for Most Common Distributions

A good program has packages for most common distributions, or such packages can be easily prepared.

Lack of such packages will require installing it from source, using generic binary packages, or other workarounds that are harder than a simple command to install the package from the package manager, and may prevent it from being maintained into the future.

A good example for how this can become wrong is the qmail SMTP server, before it became public-domain. The qmail copyright terms prevented distributing modified sources, or binary packages. As a result, the distributions that supported it packaged it as a source package, with an irregular build-process. Since the qmail package had its own unconventional idea of directory structure, some of the distributions had to extensively patch it. This in turn prevented more mainstream patches from being applied correctly to correct the many limitations that qmail had, or accumulated over the years due to its lack of maintenance.