Just like you have a budget for the amount of money you can spend, you will have an amount of complexity/uncertainty your team can handle.
If you go over budget, the project will fail or slow to a crawl.
When in doubt or when the newer tech is merely an incremental improvement I will go for boring tech.
But sometimes a non boring technology has large enough benefits that make the risk worth it.
Just like you have a budget for the amount of money you can spend, you will have an amount of complexity/uncertainty your team can handle.
If you go over budget, the project will fail or slow to a crawl.