Model Run when Sources are Ready

Hi, I am wondering what the best practice\mechanism would be to trigger a model only load when all the underlying source data is ready. I understand source freshness can be used but I understand the model would need to be run to check freshness. Which looks like continuous polling. Is there an established practice to monitor source readiness and then start loading the model only when all input sources are ready? We are using Snowflake with data being sourced from csv files from Azure Blob.