Firstly, when you create your items in TL make sure you are not in guest mode.
Do NOT click the 'Open a sample Turbo Lister file' button, click 'Set up a New Turbo Lister File'.
Remember to back up your database often and also to Compact Database (Tools ->Compact Database).
The updates do more than application changes. They also update TL tables to keep in sync with eBay's online application. This includes categories, listing designer themes, item specifices, etc.
Also, at some point you have to apply application updates to keep the program current.
Depending on what facilities you use you can eliminate some downloads. Using Tools->Options->Advanced Options->Program Updates will let you disallow automatic downloads at TL startup, turn off listing designer updates and restrict item specifics updates to categories that apply to your listings.
Good luck and you can always ask here or on the Q&A board, if you have any problems.