Are you trying to decipher an ancient manuscript? That’s a Symbology test at 6 Ob.
Situational modifiers always apply to tests, so if you flesh out the details well enough, you can find ways to apply meaningful obstacle modifiers. And when applied correctly, you wind up ramping up the pressure on the PC’s.
And it’s really something I do once a player is past the point where routine tests matter for advancement. But I should clarify: I dig around for an appropriately high Ob within the rules. So they want to decipher Auntie Z’s Cookbook of Lore? Well, what do they want? Do they want a recipe? Ob 2. Ancient lore? Ob 4. Do they want to find an incantation in there? Ob 5. Let’s add a +1 Ob modifier in there because the book is old and the ink is smudged. Maybe a horde of goblins is bearing down on you - +1 Ob because of the distraction.
Routine actions I am more likely to just say yes to
This is a bad habit. You should only Say Yes when there is no interesting consequence of failure. If a task should be Ob 1, they still need to roll for it.