The first 90 days should be diagnostic before they're executional: auditing what's currently working, what's being measured (and whether it's the right thing), where budget is going, and what the actual bottleneck to growth is. Only after that should a fractional CMO start resetting priorities or channels.
By the end of 90 days, there should be a clear plan with named priorities, not just a list of things that got fixed — this is how Kando structures its own fractional CMO engagements, diagnosis first, resets second.