not much, since I don't use Google account at all but if I lost my Outlook account which I use for exchange calendar, contacts and email sync, calendar and con

not much, since I don't use Google account at all but if I lost my Outlook account which I use for exchange calendar, contacts and email sync, calendar and contacts would be no problem since they are at any time offline in phone, so just need to be backed up and moved elsewhere, email would be bigger issue, I would need to notify my client company about using my new address and then somehow try to change email address and many services I used this email