If all is old, not uncommon, then 10% capex might work over a 20 years or longer horizon but keep cash reserves to possibly invest in it much earlier, like in 3 months.

We know there is a new roof on the horizon but we expect that.  

Invest the money, and let it sit for 30 years or more (im in my early 20s, so I have a long investment horizon).

After watching thousands of transactions go through companies I didn't particularly like (such as Equity Trust), I've had the best success with Horizon Trust and Accuplan agents.  

This is a great place to be part of with so many folks trying to help each other.My primary goals are passive income from real estate investment with a 10 to 15 years time horizon.  

Hey Holly - what is your investment horizon?

I think there is a huge opportunity in Las Vegas right now especially with what is set to arise in the horizon.

If you have a long time horizon then yes.

You still have upside potential on the units you do not pre-sell, but that comes with downside risk.Possibly, you could use prefab (modern prefab housing can be of the highest quality) to control for costs and shorten the time-horizon of the project.

Assuming an investor puts 25% down on a property, a typical breakeven horizon is 5-7 years.