Hello.
As I see, there are both Now and Today functions available in the automation rules context, while field formulas have only the latter, is that behavior intentional?
I’d like to get the current date and time to be able to calculate hours passed since the DateTime value in the other field of the entity, but not sure if that is achievable with such a limitation.
Best regards
Now() is not available in formula fields since it would imply that the formula would need to be recalculated every minute of the day, and this would overload the Fibery backend.
How would you like to use the result of calculating hours passed?
Perhaps you might find it more appropriate to use a scheduled automation…
That does make good sense, haven’t thought about it from the implementation point perspective.
Feel free to mark this topic as resolved, I see now where it’s coming from. Appreciate you handling it that fast 
What I was trying to implement, is sending a notification about PRs not reviewed in a timely manner. And I was actually writing it as a scheduled automation, where I’ve got an expression repeated quite a lot of times, making the logic pretty unreadable. So, in order to make the expression more concise, I’ve tried to extract the repeated part of the expression to a formula field on the entity just to find out that there is no Now function there.
Perhaps, a possibility to introduce variables or some sort of automation-local formula fields will be a solution to that.
I recently discovered the Google sheets formula keyword LET, which creates a “local variable” or alias just within a single formula.