I have only recently began running a scope down the main drain line and I will do that on all new purchases. 

Houseflies can lay eggs on food sitting out or even in the drain of a sink, when the maggots hatch you'll have a swarm of flies on your window. 

I'm going to be a bit of a contrarian to the above posters, but let me first qualify my post by stating that your market will determine what you should do.We frequently install en-suite laundry in our units - in fact, we have removed common coin-op laundry in most buildings of 6-units or less in favour of en-suite laundry - for the following reasons:electricity and, in most cases, hot water costs are transferred to the tenant;where water is sub-metered, water costs are transferred to the tenant;high-efficency residential laundry machines are about half the capital costs of commercial coin-operated machines;we can command $30 - $50/month in additional rent with en-suite laundry;by installing our own machines, we know they are installed property, with catch/drain pans and {going forward} leak detect shutoffs; andwith en-suite laundry vandalism of laundry machines has been non-existant ... and if a machine is damaged, we know who is responsible.We have a good rapport with a couple of local appliance suppliers and get called whenever they have "dinged and scratched" units to unload ... a small, cosmetic dent in the side of a washer - which will never be seen when it is installed in a laundry closet - can be worth a 40 - 50% discount.  

I got very basic siding, window, roof, basement French drain system, electrical, pool removal, dumpster rental... pricing simply by being honest and asking about cost.

I'm 26 and  my husband and I want to be involved in real estate investing SO SO BAD.We just opened a moped/powersports dealership together which was very difficult and draining on our finances and credit.

But when we turned on the water on the kitchen sink they had not hooked it up right, the pipe was loose and water got all over the floor and ran down into the basement through the drain lol. 

Also, she threaten to put cement down the drains and to burn the place down.

I have sprayed tubs with epoxy paint using my Porter Cable pancake - just remember to drain all the water out first and/or get a water trap. 

One of my houses has a cracked sewer pipe so the tenant can't use drains.

There is a cabinet in the hallway that allows for inspection of the plumbing, and after further inspection, the joist that the shower sits on is cut to allow the drain line for the shower to fit.