I don't withhold $12.37 per month to replace a roof in 20 years on a SFR.

-I currently work full-time and my annual savings is ~$10K.My goal in getting into real estate is to merely replace my income so that I can live off passive income and quit my job.

Many of these properties can be purchased far below replacement cost, which also mitigates risk.You are wise to question financing risk and are asking all the right questions.  

We would like to replace my wife's salary in the next few years with passive cash flow so she can raise our kids full time.

I have a cash offer in on a 10 year old, 1069 sq Foot,  3/3 Townhome that needs more than a little work (Replacing the carpets and linoleum with laminate floors, sanding, minor patching, painting walls, and re-seeding a 500 sq foot back yard), but not a full rehab. 

There is nothing else to replace it.

At this point, you could still "sell" and purchase a replacement rental property using a 1031 exchange.  

The shingles that were replaced in the Ice storm of 2009?

Familiarize yourself with prices of everything so there are no surprises when a contractor tells you it's going to be $2,000 to replace a water heater (no thank you!) 

I have just replaced carpet and pad in bedrooms of a SFR that had pet damage.