RF signals between rooms such as WiFi and wireless mic.'s

I have tenants who are leaving the house in a bad shape - the carpet is all dirty, need to clean the showers, re-touchup the paint etc. they are also leaving the couch and refusing to taking it with them.I told them their security deposit will be used for this at which point they got mad.I am worried they may do damage to the place on the last day (eg clog the drains or I don't know what all) and I can't do anything. 

I have always been fascinated with real estate, but always watch from the couch.  

I purchased like new off craigslist for couch loveseat,, only staged main living areas,, no bedrooms .Left the main living areas and kitchen, and bath staged for showings..I did add some beautiful flower pots outside and a patio table set for deck.Accessories, I kept the tags on and returned the stuff after the house was sold so basically within 2 weeks, and dragged a few things from my own home like lamps, to use. 

@Shawn Couch Hello Shawn.

Some stagers pick couches and rugs according to personal preference... doesn't always appeal to everyone. 

Love to hear your thoughts on pull out couch vs not.

Get off your couch and knock on doors, or drive around writing down addresses and start sending mailers.

In the areas I invest in I can see any and all mortgages / liens recorded on a property from the comfort of my couch.

But my main question is, imagine I bought a house, and instead of leaving it blank, decorated it and the rooms with some couches and pictures maybe even a flatscreen tv (assuming I got it all free and not stolen) etc etc etc and I'm not talking about paint, just the stuff you put in your new house to make it feel at home.