My granularity is: Different things go on different commits. For example, you can include 30 files and hundreds of lines in one changeset if they are all relate

My granularity is: Different things go on different commits. For example, you can include 30 files and hundreds of lines in one changeset if they are all related to the new feature X, but do not in the same changeset correct the indentation of a code block. The commit message is like a title. All diff lines must be related to it or they should be in another changeset.