Your very first backup is a full backup and therefore this will take the longest time to run compared to your subsequent daily backups. Once your first back is complete though, your daily backups should complete within a couple of hours i.e. daily.
There is really no easy way to calculate how long the first backup will take as it comes down to quite a few factors, just like how long will it take to sail from A to B? Some Xero organisations have taken a couple of weeks, some even longer, but most small Xero organisations complete within a couple of days.
Factors to consider are how many records do you have in each Xero table of accounts, there are more than a dozen tables, for example your Receivables and Payables, your Bank Accounts and your Customers and Suppliers etc. If you are using Xero’s ability to store attachments, you are also going to need to allow time to back these up.
Xero also limits the amount of requests for data in a 24hr period. Once you hit the limit, controlc have to wait until the next day to pickup where it left off.
If you think your first backup is taking way too long, then you should contact us at support.controlc.co.nz and we will look into it for you and let you know its progress.
Hope that helps.