Tough question and I have done close to 100 so I have a pretty large body of evidence to draw from In general my advice would not to waste money doing one before approval. I would also not write an offer and try to buy one that was a fixer and not in good to very good condition knowing i wasnt going to get repairs. Condos work well as short sale buys as do newer homes. Older homes with lots of issues dont work so well unless they have fallen out due to a previous buyer walking over issues uncovered during an inspection.