For example, I used the plugin Vote it Up but it haven’t been updated since 2010-5-28. Now I moved to GD star rating which was last updated in January 6, 2011 (and still maintained by he author).
Is it not recommendable to stick with plugins that are no longer supported by the author for production sites?
As for me key questions here are:
What do you think? 😛
Snarkiness aside, it depends on wether you have the necessary resources to maintain it on your own, should the need arise (either doing it yourself, or hiring someone).