<p>I'm going to be distributing a plugin that will be routinely updated with features, bug fixes, and updates to downloadable corpuses.</p>

<p>The usual update site mechanism can do the update ok - when the user asks it to.</p>

<p>The problem is that (unlike MS Office), the automatic updater preference is off by default and I don't want to change that default for my users or count on them changing it. </p>

<p>Can I write something that occasionally checks for updates? Or prompt the user regularly? What's bad form and what's acceptable ?</p>

Eclipse 3.4 check automatically for plugin updates by default.
You will see a popup window in the bottom right when an update is available.
To configure automatic updates, go to Window > Preferences > Install Updates > Automatic Updates