Like you I plan to begin in multi families and commercial real estateA book I just finished that provided much information and resources is a book by Don Pebbles: Path to building real estate wealth.

Look at your competition to see the types of finishes they're using.

They don't know what your finish level will be when you're done3.

It was a huge rehab, so it took about 8 months before I finally finished.

The house needed a lot of work that at first just looked like small jobs but quickly added up to be a massive project and at the time we had other larger projects underway and this house took 4.5 months to finish.

Look at the lease your future clients will sign with them, ensure you know what their fee structure is from start to finish with tenants. 5.

We learned that cheap contractors are not worth saving a few hundred dollars if it means they take 10x as long as they expect to finish the work.

Tenant-2 wants to stay in the house and finish out the lease (which is only a few more months) but he can only afford half the rent payment.  

That's very dependent on the market, size of the property, class of neighborhood (low or high quality finishes) and end use of said property (rental or flip).

The key is to know what the trends are in terms of floor plan, finishes etc. and to know what the values are and not overshoot.