Create your own Deprecation Checker page or post

<strong>This site is only for checking for Deprecated Functions.</strong>
<ol>
    <li>Install the plugin (<a href="wp-admin/plugin-install.php?tab=url" target="_blank"><span style="background-color: yellow;">via URL</span></a>) or theme (<a href="/wp-admin/theme-install.php?tab=url" target="_blank"><span style="background-color: yellow;">via URL</span></a>)</li>
    <li>Do NOT activate the plugin or theme</li>
    <li>Run the <a href="/wp-admin/tools.php?page=deprecation-checker/deprecation-checker.php" target="_blank"><span style="background-color: yellow;">Deprecation Checker plugin</span></a></li>
    <li>If "dirty":
<ol>
    <li>Look at the actual plugin/theme code on the specified line number(s) to see if the deprecated functions are used only when an old version of WordPress core is being used. This may be a feature, not an error. They would probably be contained within some "if" logic.</li>
    <li><a href="http://wordpress.org/extend/" target="_blank">Report</a> any suspected incorrect usage of deprecated functions to the Author (or fix it yourself and submit a patch)</li>
    <li>Install all future plugin and theme updates</li>
    <li>Re-check, using Deprecation Checker plugin</li>
</ol>
</li>
    <li>If "clean":
<ol>
    <li>You may permit yourself to consider using the plugin or theme</li>
    <li><a href="http://wpmu.org/donate-1-to-every-free-wordpress-plugin-you-use/" target="_blank">Donate to the Author</a> if it was free</li>
</ol>
</li>
</ol>
<div><strong>And repeat the steps above using additional scanners...</strong></div>
<div>
<ol>
    <li><a href="/wp-admin/themes.php?page=themecheck" target="_blank"><span style="background-color: yellow;">Theme-Check on my WP</span></a></li>
    <li><a href="/wp-admin/plugins.php?page=plugincheck" target="_blank"><span style="background-color: yellow;">Plugin-Check on my WP</span></a></li>
    <li><a href="/wp-admin/themes.php?page=tac.php" target="_blank"><span style="background-color: yellow;">TAC check on my WP</span></a></li>
</ol>
</div>
<strong>The ONLY plugins that should be activated are:</strong>
<ol>
    <li>Checker plugins
<ol>
    <li><a href="http://wordpress.org/extend/plugins/deprecation-checker/" target="_blank">Deprecation Checker</a></li>
    <li><a href="http://wordpress.org/extend/plugins/theme-check/" target="_blank">Theme-Check</a></li>
    <li><a href="http://wordpress.org/extend/plugins/plugin-check/" target="_blank">Plugin-Check</a></li>
    <li><a href="http://wordpress.org/extend/plugins/tac/" target="_blank">TAC (Theme Authenticity Checker)</a></li>
</ol>
</li>
    <li><a href="http://wordpress.org/extend/plugins/upload-theme-via-url/" target="_blank">Install via URL</a> (for quick and easy installations)</li>
    <li>Any update plugins (to keep your plugins and themes updated so they can be re-checked), like <a href="http://premium.wpmudev.org/project/wpmu-dev-dashboard/" target="_blank">WPMU DEV Dashboard</a></li>
</ol>
By never activating any plugins or themes other than the ones above, you never risk the extensions adding "upon activation" items to your database.

An additional benefit this structure provides is a holding space for all the plugins and themes you currently use, once thought about installing, or plan to install. It'll allow you to update and re-test all extensions prior to updating on your live sites, and you'll have a central place to bookmark all those "contender" extensions (the ones that are similar in functionality that you're looking to pick between).