If you can profile your application do so, data trumps estimates every time. For a web based app your scarce resources are memory, bandwidth and database conne

If you can profile your application do so, data trumps estimates every time. For a web based app your scarce resources are memory, bandwidth and database connections, disk space isn't usually an issue at first. One factor to keep in mind is that as you add features to your app, your usage profile will change, mostly by growing heavier.