Freelancers: how do you handle “I thought this was included”?

One sentence I think every freelancer eventually hears:

“Wait… I thought this was included in the original scope?”

Sometimes it’s genuinely unclear.
Sometimes the project slowly changed over weeks of calls, emails and messages.
And sometimes you know it wasn’t included, but finding the exact conversation where it was agreed is another story 😅

Curious how other freelancers handle this.

Do you:

• keep a very strict SOW?

• document every change manually?

• charge immediately for anything outside scope?

• just absorb smaller changes to keep the relationship smooth?

• have some other system?

I’m especially curious about what actually works once a project has been running for a few months and there are dozens of conversations everywhere.

Would love to hear how you deal with it.