What problems occur when exporting Outlook PST contacts manually?

I am trying to export my contacts from an Outlook PST file manually using the import/export option in Outlook. However, I am a bit concerned about possible issues during the process. I have heard that sometimes contacts may not export properly, or some data fields might be missing. Before I proceed, I would like to know what common problems users usually face when exporting Outlook PST contacts manually. For example, can it cause data loss, formatting issues, or incomplete contact details? Also, is this method reliable for exporting a large number of contacts? If anyone has experienced this before, please share the challenges you faced and suggest a safer way to export PST contacts.