I can't stress this part enough...Stopped airlock bubbling doesn't mean a stuck fermentation, or that fermentation is done. It means that there is simply not enough co2 to need to be vented by the airlock. The airlock is a VENT not a fermentation gauge.
Fermentation is not always "dynamic," just because you don't SEE anything happening, doesn't mean that any-thing's wrong,, and also doesn't mean that the yeast are still not working diligently away, doing what they've been doing for over 4,000 years..
And just because the biggest "push" of fermentation is over where the yeast aren't throwing off a ton of co2 and blipping the airlock, and even that the krausen has fallen, doesn't meant that fermentation isn't still chugging away, just slowly. Or at the minimum the yeast aren't cleaning up the byproducts.
Your hydrometer is really the only way to know for sure. If you don't take a reading then leaving it about 2 weeks before racking to secondary OR leaving it for a month primary like many of us do, will make sure the yeast have finished their jobs.