The house I purchased was recently renovated so rehab wasn’t a factor in this deal, but being a STR I wanted to go with higher quality furnishings that would stand up to more abuse. (2 years in and that has paid off so far) But I went about 20% over my estimated budget.

We have seen both cases, renovated vs not renovated apartments from our clients and the renovated Units rent for much higher returns and the quality of the tenants are much better too.

Calculating an ARV seems to be an easier task, because I can evaluate the sale prices of similar properties in the area, with respect to size, quality and location.However, estimating rehab costs is difficult.

The barrier of entry is high for quality STNL's but it protects my downside and fits my investment strategy of stable predictable cashflow. 

Chavez, they were fast, reasonable, and did quality work. fchavezpaintinginc.com 

There is going to be a trade-off between cost versus quality.

Your capex and repairs MiGHT be higher, although they could also be lower if it’s a quality rather than size difference in prices.

It may be frustrating to know that you'll have big ticket items coming, but consider it your version of philanthropy to the city.You take a less than beautiful home, and through quality ownership, make it a better part of the community.

Quality goes a long way.

I get more responses there than Zillow however they aren’t as good of quality but it is a start.