Azure DevOps - Conditionally Build and Deploy Say we have 6 microservices in a monorepo, each with their own CI build pipeline that is currently only building each project and running unit tests. Is there a way to identify which projects have had code changes since the previous release and only build and deploy those, leaving others untouched? I've not seen anything in the documentation examples that describe this as a possibility but I'm hoping that with all of the conditional and scripting abilities in YAML and possibly templates, never used them, that I could achieve this. 

One way forward without this would be to manually comment out the services that I know had no changes in the YAML and commit that, then build from the updated definition. This is open to human error so I'd like to increase the level of automation.

Builds - Get Changes Between Builds
Something like this looks interesting but I'm not sure how I'd integrate it with YAML

The goal of all of this is to only version stamp and deploy what has changed. I may be missing some core DevOps concepts here and am happy to read more if you'll guide me.
You can create build pipeline triggers to trigger your builds based on branch along with path triggers. In your release pipeline, you can set triggers and filters to decide which artifacts to be deployed.