In many situations, an older property can be PREFERABLE to a newer property.One of the biggest misconceptions by inexperienced RE investors is that new houses are inherently less costly/less headache to maintain, and inherently "better" than older houses.

Biggest challenge is that I didn't really know how to evaluate the property expenses at that time.

My biggest financial mistake was only contributing up to company match and nothing else.

Typically a roof is the biggest one time expense we experience so we usually aim to have at least the cost of a roof in liquid cash.

Leveraging your existing relationship’s- This is my biggest suggestion and first thing to do when you need a project done and for getting more than one quote.

Raising rents to market rate was the biggest value add. 

Biggest thing to consider is whether you can use real estate losses to offset other income.

Your biggest mistake is in giving applicants the "benefit of the doubt".

Change orders are one of the biggest reasons why it is so hard to keep a project on schedule.

The biggest challenge in the early years was getting over the nerves to jump in and buy and 2nd problem was being too sympathetic to the potential renters stories and why their credit was bad on what ever excuses they had.