I've yet to run into any limitation.
If whatever plug or device to monitor washing machine or dryer, you just tell it to open a virtual contact sensor when you want.
Under alexa you just say when this contact sensor is open to speak "Washing Machine is done"
Here is an example how I’m taking advantage of this.
Nobody is home based off motion I open a contact sensor that is exposed to Alexa.
Alexa sees that it was opened and it tells my Xbox to turn off. My Xbox turns off.
I’ve also done, if my Lutron Remote is held down in the basement to turn my lights off and open this contact sensor which Alexa shuts off my Xbox.
I also use it for when my front door is left open. When triggered Alexa says front door is open.
Now getting off topic. I’m looking at broadlinks or one harmony hub setup in my network rack with IR RF extenders to all my tv and units.