A big part of the Tap Inspect system is the servers that sit behind the scenes and take care of the heavy stuff for you. The Tap Inspect app needs to talk with those servers from time to time and stay in sync.
Tap Inspect syncs about every 5 minutes in the background while you are using the app AND you are connected to the internet. If the app is not on the screen or if you are not connected to wifi or cellular data it will not.
For cellular connected devices this works quite well and you may never even notice Tap synchronizing. For wifi only devices you may need to take a little special care.
After collecting all the inspection information and adding all your photos all that data needs to be uploaded and that can take time. For wifi only devices you may need to manually synchronize too.