Previewing your NSF file before conversion helps you avoid unnecessary exports and confirms the data's integrity. One of the things I appreciated about using eSoftTools NSF to PST Converter Software was its built-in preview panel. After loading the NSF file, I could see emails, attachments, contacts, and even calendar events before starting the actual conversion. This was very useful for selecting only the necessary items and avoiding extra clutter in my PST file. If you're doing selective migration, preview features are a must-have.