Actually, I find the air lock bubbles to be a fairly useful way to track the progress of fermentation. When you watch for several minutes and see no bubble activity you can assume fermentation is nearing completion. Then use your hydrometer to check SG to verify your “assumptions”. I also use time to aid my “assumption” as generally I find primary fermentation of grape juice must to take at least 10 days before transfer to secondary. I’m a little unconventional in that I like to ferment to dry in the primary and I transfer as little of the lees (sediment) to the secondary as possible. For reds, the wine remains in secondary for about a year, being racked to a different carboy at about 3 month intervals, again leaving behind as much sediment as possible. After a year the wine is clear, very little or no sediment in the final carboy and wine has been naturally degassed. About a year ago I began using a vacuum system to transfer the wine from primary to carboy and from carboy to carboy at 3 month intervals and I find that this process clears and degasses the wine faster but still I go through the full year process. I feel reds are generally better if aged for at least a year so one year in a carboy is not a problem. White wine is another issue. I haven’t figured out why, but my whites from juice, using this same process, often end up with cloudy or crystal tartrates in the bottle after a year or so in the bottle. I’m not a real fan of whites anyway so I have stopped making them from juice and gone back to kits. Following kit instructions I can bottle a kit white as soon as it clears (5-8 weeks) and enjoy a white wine that stays clear in the bottle. Go figure???