ideally you want devices (or external integrations) that report state changes as they happen, when you have such devices there is no need to poll them for their current status.
This is easy to figure out with devices such as motion. contacts, thermostats, dimmers and switches.
You open the mobile app, walk over to the device, make some change to it, see if it updates in the app.
If it does, all good, if not, well at lease now you know.
(The above presumes, that your hub, the device and ST are all function correctly of course)
Some devices that don’t report can be changed via programming, some can’t.
For those that can’t report state changes in a reasonable time, if ever, that’s where polling comes in.
Folks use pollster, RM or roll their own for this.
In order to poll a device, the device needs to support the capability polling and or refresh, generally refresh if implemented in the DTH is exposed in the device details where it can be activated manually.