I would argue that even more important than the time spent, is the consistency.

There are a ton of other great books with sections on estimating rehab costs  I've personally read these:The Real Estate Rehab Investing Bible by Paul EsajianThe ABCs of Real Estate Investing by Ken McElroyThe Millionaire Real Estate Investor by Gary Keller, Dave Jenks, and Jay PapasanThe Weekend Millionaire's Real Estate Investing Program by Mike Summey and Roger DawsonGood luck with your endeavor!

My wife and I love the Million Dollar RE agent and the Million dollar investor by Gary Keller as well as The Abcs of Commercial Real Estate investing by Ken McElroy.

I would even argue that it is getting worst. 

People will argue til they're blue in the face on Turnkey versus Rehab and those people never take action.

Still curious if anyone out there would argue differently, but I doubt it.  

They argue: How can you determine if a condo is used strictly for vacation property income?

Just as the pre-crash "Stated income" loans presented a moral hazard, this is similar, some argue.

However, some people argue that you make "more" from holding on to the appreciating asset than you pay in PMI costs.If you own a home and live in it as your primary residence, you wouldn't 1031 your cap gain profits.

People argue that a face makes it more personal but i feel like that's more diverging from your business.