Yes, that's right, @adreher1.
In QuickBooks Online (QBO), you can only restore those deleted projects with unfinished transactions. Those projects that were marked as "Completed" before they were deleted cannot be recovered again.
If you want to bring back those projects you can recreate them instead.
Then, to easily track the labor costs and profitability of your projects, you can use this article as a guide: Track hourly labor costs and profitability by project in QuickBooks Online.
I'm always around the corner if you have other questions regarding projects. Drop a comment below. Have a good day ahead.
