Yeah just access how he is doing, how he talks about money, how much much he has disposable, see if he has reserves and credit. 

The one that has a garbage disposal has seen no problems.

But I’m talking about people with $30k+ of disposable income a month.

Here's what I generally pay (remember, this is my area, my contractors, etc, so it may not be apples-to-apples in your area):Water Heater plus Expansion Tank: $125 (done by plumber)Gas Range: $25 (done by plumber)Fridge Water Line: $15-25 (done by handyman)Dishwasher: $75 (done by plumber)Garbage Disposal: $50 (done by plumber)Built-In Microwave: $40 (done by handyman)Washer/Dryer, plus Venting: $25 (done by handyman)Oftentimes, my project manager will do most of these things, so it's actually free, but if I'm paying my contractors, this is about what I expect.

Those "soil conditions" = construction debris of various sorts (bricks, lumber scraps, roof shingles, concrete, foam plates and disposable coffee cups, etc) at very shallow depth.

They are like giant disposable zip ties used to clear out drains.

I just made the transition from renter to owner, and if Oakland were a free market my rent would have jumped up by $1100/month in just one year.As long as there's a time where the rent can reset to market rate, I think rent control actually drives property appreciation faster than it otherwise would.The trick as an investor is to know the laws, and use the tools at your disposal to get your rents up over time.

To me, that signals more, not less, disposable income.

Those tenant/buyers tend to have more disposable income that can be used for option deposits. 

They are cheap enough to be disposable after a tenant wrecks one.