Development best practices - expression vs Inline queries and Git

We have a large number of snap pipelines inherited on a project and I wanted to ask for some best practices on maintaining those pipelines.

• How much should we put in expression files? Should we put all of our queries in SQL snaps in expression queries or leave them inline?
• We use Bitbucket for source controls? What is the best practices for checking in and out our code there?

Thanks!