I use Tilt hydrometers and SG is tracked in Brewfather. Every brew reaches the expected FG. However, there is still some slow fermentation activity for a few days to a week after reaching FG, resulting in a lower FG than anticipated, and thus a higher ABV. My usual process is to wait until there is no change in gravity for 2 or 3 days. I am not in a hurry to keg, and I don't have a reason to keg at FG. My beers are usually a few gravity points lower than anticipated, but I haven't been able to say that any have been too dry or have any other negative character due to the lower FG and higher ABV. This occurs with all of the yeasts that I use and all of the beer styles.
Example: I currently have a beer in a fermenter that has an expected FG of 1.011 which was reached on Friday, then was 1.010 on Saturday, 1.009 on Sunday, 1.008 on Monday, 1.007 today (Tuesday) and is slowing down. I anticipate that it will stop at 1.007 or 1.006.
Can I keg at FG, or should I wait until there is no change in gravity for several days to ensure that fermentation is complete, off-flavors have been cleaned up, the beer has dropped clear, etc.?