There are lots of factors to consider when stopping an experiment.
1. You probably want to run for at least a full week to get both weekend/weekday traffic (unless it's looking really bad, then you can stop earlier)
2. If the Risk column is really low for your key metrics, it's safe to stop since even if you're wrong it won't have a bad impact.
3. If Chance to Beat Baseline for your key metric is above 95% or below 5% and the Risk column isn't too big, it's also a good indication you can safely stop.
4. If there are any external factors like a big marketing campaign or holiday that are affecting results, you might want to stop the test to avoid conflicts.