Loss of granules is a sign of roof aging.  

At age 29 I found myself supporting a wife, an ex wife (child support) and 2 kids on food stamps and working for minimum wage.

I did invest at a young age but left investing behind.

The kids are good kids but they are hyper due to their young age.  

In May 2016 those tenants bought a house and moved out (with a month remaining on lease that they paid) and we rented it the same month for $1900 (incl pet rent), again to a stable, middle aged couple.

What do you expect your maintenance rate to do as your portfolio ages and capex items need repair or replacement?

I wouldn't worry about your age at all.

Some retirement accounts aren't accessible until you quit your job or hit a certain age and they typically won't accept those kind of reserves.  

The vast majority of soldiers are not at an age to be home buyers.

I break it down like this (5% - $22.50 Vacancy5% - $22.50 Credit Losses (Uncollected rent and skips)10% - $45.00 Property Management5% - $22.50 Maintenance/Repair10% - $45.00 CapEx (Depends on age of property)5% - $22.50 Tax and insurance10% - $45.00 Utilities, Landscaping, HOA fees, etc.5% - 22.50 Misc (Pest Control, Legal, Accounting, Leasing)Total = $247.50Common Expenses to look for (What you provided):Vacancy ($22.50)Property Taxes ($30.83)Insurance ($25.00)Maint.