@Nathan Gesner
Pro's: I see the tenants and can set screening criteria. I learned to recognize tenants who will likely stay. I have taken new renters who meet my minimum financial criteria over higher score person "looking for a house" or someone who says they are staying but really is just looking for short term. (how many times did they ask about the lease break clause?). Was the last job seasonal? (We are in a seasonal area with year round units being less available). A new to the area 20 something with a strong local employer may be a more long term occupant. I know that isn't something a PM will pay attention to. Also I can pick shorter term tenants if I have plans to reno a unit.
Hard lessons:
-unexpected things will happen at the worst time. starting a vacation in the BVIs and you get that dreaded tenant call. the window fell out or there is a heat issue.
--Issue lease violations- tenants will do things you can't think of. Hanging a large boat motor from a tree. Using a bedroom as a workroom. burning pallets in a firepit so you have 9000 nails to dig up when they leave.
Be proactive**** Fix it the first time. If the sewer backed up there is a reason. I wished I knew about scoping a sewer line before I bought my first property, I would have done it with the septic inspection. Even if you have 2 backups 3 years apart it is likely there is something wrong with the line. Put in a no dig cleanout for the septic because problems won't happen in daylight. Septic filters are a PIA. If that vent on the furnace failed before or a zone valve failed it will fail again, have a service contract or have a spare part on hand.
Be prepared to lose vendors and recognize when a vendor is too small for a job. Our oil company suddenly wouldn't service if they don't deliver so we had to find a new 24 hour service. And if your electric contractor is one man, he likely can't put the 40 foot service line back on the building.
If the tenants are on a downward spiral they won't get out of it even if they rationally can. If they can't pay now eventually they won't be able to pay and they will take forever to get out. It doesn't matter how old or sick they are or if you like them.
If a tenant is causing too much stress for you don't offer them a new lease. I had one guy who complained about the upstairs tenant walking loud, he just wasnt' suited to the building. No complaints for a bit, I offered him a new lease and two weeks later he is at it again. I went to his door and said this is the way it is, here is your happy clause, you stay, no more noise complaints or you can just go now, no penalty. He went.
Always go over the lease in detail and explain policies like repair access to tenants. The medical pot growing tenants didn't want anyone in their house when they weren't there. After that I always cover that tenants will have to work with vendors for repairs and if they can't accept someone in their absence they have to arrange their schedule to meet the vendors, not the other way around.