Ok, ok - guesses aside, I always go with my gut.
That said, I don’t do it to unreasonable lengths.
If I’ve got two players of perceived equal value I play the matchup.
I usually evaluate in this order:
1. Always start your studs.
2. Always start your studs.
3. If one of your best team is out, hurt or has not lived up to expectations (R.Freeman, Collons, for examples) I would likely stick with them unless matchup dictates otherwise. For example, I’m starting Collons in one league at RB2, but benching R.Freeman (for Murray) at RB2 because he’s underperformed AND has a bad matchup.
4. If a peripheral player is hurt that impacts my player’s potential productivity. Ex: if a key OL goes down, or a QB if I have the WR/TE.
So “go with your gut” is a bit of a misnomer - sure, we all have gut-checks on the weekly...but you gotta evaluate the data too, to form a gut feeling.
Otherwise you’re just throwing darts every week.