And the other things, while you should plan for them with some monthly holdbacks, may only arise every couple years, like a plumbing leak, or an HVAC repair, or leak in the roof.  

A small leak in the hot tub and decks that could use a good staining are on the list.

They have a water leak and it’s been about 2 weeks. it’s going directly underneath my house to the point that it looks like a lake under my house.

Since you're talking about a leak...Did they have a plumber inspect or a roofer inspect?

Cars shouldn’t be leaking oil.

I consider it a cost of doing business and I really dislike LL who have paid poor tenants to leave and believe they have taught the tenant a behavior that is hard to detect in the screening process.  

After discussing with my contractor, since there is nothing backed up or leaking and the toilets and sinks are draining properly, there is nothing to repair or replace at this time.

When you get the 2 pm call that the kitchen sink drain is leaking and you are filling a cavity in someone's molar, you can't exactly get up and leave to take care of the sink. 

The reason the shower is being replaced is because they notified me of a water leak coming from the shower.

I blew insulation inside the house and also found some roof areas that were leaking a small bit.