I use webCore to notify me when the door has been open for some time. But another thing you can do is run a check of things like garage doors automatically at night time.
If you are using the Classic app, set up a routine to run in the evening. Have it check the garage doors and notify you. If you have your garage doors automated, you can even have the doors automatically close when that routine is run.
(www.rboyapps.com - Making SmartThings Easy!)
The simplest way would be to create a standalone rule and use SHM Monitoring in the Classic app or create a custom automation in the new app.
However if you’re using the RBoy Apps LUM app, it has a built in door open monitoring function which you can use to monitor your garage door and have it notify you using a SMS, Push or spoken announcement.