Currently, notifications for completion percentages reached in a city are every 5%. If running a large city, with thousands of streets, this results in what I would classify as a reasonable frequency of notifications. However, when it comes to smaller cities, nested cities and potentially cities that are clustered closely, this results in every run producing one or more notifications (more if it covers 2+ bordering/nested cities). Personally, I find that frequency/number of notifications to be a bit much.
My suggestion is to allow the user to specify the frequency at which such notifications are produced. This does not need to be so advanced that it allows the user to specify all the thresholds they want to receive notifications for. Instead it could be as simple as allowing the user to select from some predetermined set of thresholds. For example, one could have the option to receive a notification at every:
- 100% (only on completion)