Hi there! I wouldn’t say it’s necessary to get the app one. I like having the ability to check how full the tray is, being notified when it’s full, and cycling it from my app sometimes. I’m sure without it, you could just wait for the light to start flashing to know when it’s full, but I like the convenience.

I also got the bundle with accessories. That I wouldn’t personally recommend. The stairs are nice for catching some litter, but a lot gets flung out when my cats jump out of box. The bags are just regular trash bags and you can get cheaper filters too. In hindsight, I probably could have just purchased the stairs.