There are a few reasons you may not have received a notification about your trip. First, make sure that you've allowed notifications for price predictions in the app.
Flight prices fluctuate constantly throughout the day, so Hopper will only notify you if prices change drastically or if we think you should book. We'll also send you a warning notification if we think prices are going to start to rise. However, we may not notify you of insignificant price changes unrelated to our prediction.
If your trip is far in the future, we may not send you too many notifications at first. Some airlines don't set their schedules until six or nine months ahead of time, and we don't want to bother you until we have better data. However, you will receive notifications when your departure date draws closer.
If you are manually checking prices for your trip in the app, we won't tell you about a price that we know you've already seen. Our system tracks the prices you have seen so we don't send you repeat notifications or redundant information. This means that you may not be receiving notifications simply because you are manually checking on your own. It's OK to do that once in a while, but we do recommend waiting for notifications.