Service Engine Soon

What does this mean exactly?  Does this mean soonish, like I have a couple weeks or even months?  Or does it mean within minutes or my engine is going to explode into a million pieces.   The dashboard should have lights for every part of the car.  If a belt is going to break that light should turn on.  If your engine is going to explode a light should come on for that so you can at least get out of the way.  Obviously a woman's opinion was not asked about this matter.  In that case, I'll just ask my very nice husband to take my car in for me...okay honey?