Powershell – Copy items from Source to Destination if they don’t already exist

I have a pretty basic powershell copy script that copies items from a source folder to a destination folder. However this is moving way too much data, and I'd like to check if the filename already exists so that file can be ignored. I don't need this as complex as verifying created date/checksum/etc.

Currently it's along the lines of:

Copy-Item source destination -recurse
Copy-Item source2 destination2 -recurse

I'd imagine I need to add the Test-Path cmdlet, but I'm uncertain how to implement it.