Provide script-accessible version info in your plugins
From Vim Tips Wiki
created April 25, 2008 · complexity intermediate · author David Fishburn · version 7.0
Most plugins have something like the following at the beginning:
if exists('g:loaded_dbext') || &cp finish endif let g:loaded_dbext = 1
This prevents the plugin from being sourced more than once. It successfully accomplishes this task, but is essentially useless after that. So I have taken to setting the variable to the version of the plugin, rather than just 1. For example:
if exists('g:loaded_dbext') || &cp finish endif let g:loaded_dbext = 503
This way, other plugins that utilize my plugin can verify the version, and provide useful error messages or handle things as needed.