Source control is a change tracking mechanism. Use it when you want to know who changed what and when.

Source control is not free. It adds complexity to your workflow, and requires training for new collegues. Weigh the benefits against the cost.

For example, it can be tough to control databases. We used to have a system where you had to manually save definitions in a text file and then add those to source control. This took a lot of time and was unreliable. Because it was unreliable, you could not use it to set up a new database, or to check at what time a change was made. But we kept it for years, wasting countless hours, because our manager thought "all things should be in source control".

Source control is not magic. Try it, but abandon it if it doesn't add enough value to offset the cost.