For stabilized multi-tenant retail/industrial, three to four months of operating expenses plus a capital reserve appropriate to roof/HVAC age is common.

I began at about your age as well and I'm confident this strategy will give you valuable experience with acquisition, project management and property management.As far as analyzing deals and determining potential upside, I'd recommend you to connect with an investor friendly agent in your market. 

This aged well.

We always recommend thinking of real estate like a stock portfolio.Most financial planners use the "3 buckets" analogy with their clients:High, medium and low risk investments, depending on a person's personal risk tolerance and age to retirement. 

And at full retirement age so the thought of 30 mortgages is a non starter.. what few rentals we have are paid for and its exceeds your equity by quite a bit.. so instead of buying more we just rent our cash to others that want to flip homes.. thats a happy medium and far more true cash flow than owning the homes..

GFA, galvanized/copper mix, clay sewers (scope them), porch permits/condition, lintels/tuckpointing, window age, roof layer count, and water service line (lead is common).

There’s no income verification, no interest reserves, and experience isn’t required.

For me a great wealth builder was (1) a DEFINED BENEFIT plan allowing me to defer tax on up to $350,000 per year at age 50 when I was in the highest tax bracket; and conversion to and into a ROTH 401k (all self directed) over a 5 year period at a lower bracket and a BIG discount for the non liquidity of my retirement portfolio investments.  

You do NOT want to overwhelm yourselves with a major renovation on your first deal.Check Major Components: As you noted, verify the age and condition of the roof, HVAC, and water heater.

@Jonathan Warner - not to oversimplfy but historical data from your properties can serve as a helpful benchmark, but you’ll want to adjust for property type, age, and expected repairs.