It would be nice to write a guide that covers some common things people might want to do when they are using custom Serialize/Deserialize types with the driver.

For example, we could mention that if you add a field to your schema and have documents that are missing it, using an Option would allow you to handle it gracefully.

Or, if you want to rename your _id field to something else in your struct (perhaps you are using a username as a unique key, for example) we could show how to use the serde renaming attribute to do that.

We've also had a user ask about handling schema changes in the past, so we could take some inspiration from this .NET driver page on how to handle this with your custom types: https://mongodb.github.io/mongo-csharp-driver/2.14/reference/bson/mapping/schema_changes/