so, when should you actually use API versioning strategies?

Hey everyone, I've been chewing on API versioning a lot recently. We're spinning up a new service and have to pick a strategy. What do you think we should do? Put the version in the URI, like /v1/users? Or use custom headers, maybe something like Accept: application/vnd.myapp.v1+json? Or even query parameters, like /users?version=1? Each has its own pluses and minuses. What's your usual approach, and what's your reasoning? I'm really interested in the trade-offs you've seen in actual projects, particularly how it affects clients and how easy it is to make changes later on.