don't do it until you absolutely have to

Especially if you don't feel confident about database programming. ;)

update. You don't decide to use a database for your own pleasure, but because the application requires it. A recent node by ChOas explained very well that good programming is data analysis in the first place. If your analysis calls for a database backend, then you must implement it.

you should try and route all your database access through one or two modules (either tools from CPAN, or home rolled) as a way of limiting your dependencies

Using the DBI doesn't mean that you cant program in a modular way. My point is that if you are skilled enough, you should call the database without intermediate modules.
You can accomodate your programming logic inside one or more modules. By "programming logic" I mean what your application should do, not some set of rules to make the database interface more user friendly. You can build your logic either using the DBI directly or through some wrappers. I prefer the direct way, but it doesn't mean that using the DBI directly will turn my scripts into spaghetti code.

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