As for the age of the building you are correct in stating things are reaching the end of there age. 

Some of those variables are the size of the park, number of vacant spaces, number of POHs, number of vacant POHs, number of MH spaces, number of RV spaces, the park amenities, the age of the park, underground infrastructure age and condition, park location, size of the market, value of SFR in the market, water or well, sewer or septic, other utility sources and whether or not they are direct billed, deferred maintenance, cost of management, and more.However, there is a basic "back of the napkin" evaluation that will usually tell you if the deal is worth a closer look.

This is huge undertaking for a beginner however I want to practice running the numbers on this property.A little information on the propertyListed: $8,889,000County Appraisal - Improvement: $1,388,880County Appraisal - Land: $2,661,120Taxes: $125,000/yOn Market: 125+ daysBuilt: 1972Renovated: 201754 Units: 22.3% Studio, 63.2% 1Br/1B, 14.5% 2Br/2BRent between: $895-$1750100% Occupied - Average age of tenants ~35Cap Rate from Broker: 5.6%NOI: ~$500,000Assumed Vacancy: ~9%Coined Laundry: ~$500/mElectric Reimbursement: $2,500/mAdmin, Management, Turnover, Utilities (pool included): ~$100,000 Maintenance: $2,000/mInsurance: $25,000/yNeighborhoodAverage listing price: $420,000Average time on Market: 60 daysAverage price sq. ft.: $250 (SFH)Purchase InfoAssumed Purchase Price: $6,125,00025% Down over 30 years2% purchase costs: $122,000First year IRR: -3%I believe that the list price is overpriced for the area given competition.

@Alex Kenny congratulations Alex.. your thinking is on the right track for such a young age.

They are of varying ages, interest rates and amounts. 

My question is, when does the age of the building will effect the price of the condo?.

That's the legal age to sign a contract.   

I think our natural inclination to get more cautious as we age coupled with the perception that the real estate we can touch is somehow more secure. 

They are old school Industrial Age folks who are retired and want to give us their estate when they pass on.

As a kid we moved around a lot but always in or around the same city of Upland, CA, and basically would move into a distressed property, my father would rehab it, and then we would move into the next project, so I really got to see the benefits or REI at a young age.