Difference between roder et rôder
Roder (to roam): We get a car, a new formula, we try it out, and we tune it up.
Rôder (to hover): But we're lurking near a bank, which means we're turning somewhere to set up a bad job. That's how you become a prowler: un rôdeur.
To tell the difference between the two, try to see if the subject is more of a prowler or if it is something you are developing.