I did this at my first, learned quick oldheads would get flustered and feel challenged if not eased into things a certain way.

Ultimately by the time I left I tried to introduce redbeanphp (orm), git for source control, and CakePHP for some structure. Nothing stuck. When I left it was still raw sql string queries, .zip files when they remembered for backups, and 400,000 line php files with everything caked on there.