Also - Jay Scott has a book on estimating rehab costs that you might want to check out - it has a very detailed review of the home condition.
My major ones are:
- Foundation & overall structure (termites, sink holes, evidence of water damage/mold)
- Roof needs to be replaced every ~12-15 years so if it hasn't then that will need to be done
- AC - 50/50 shot if over 10 years old.
- Look at plumbing - copper might need replacing & polybutylene pipes need to be replaced
- Had an insurance company refuse to insure a property with a water heater over 10 years old...
- If houses really old you want to make sure that the Electrical Panel has been updated or you will have to in order to get traditional mortgage financing or sell.
Also check on sex offenders and school ratings if the target market for the area is people that have kids (I check before I make an offer). Heard stories of neighbors with really loud barking dogs that have killed their ability to re-sell (flip)
I relied on the title company to do all the lien searches, etc. The home was an REO that the bank had owned for about 4 months in a planned subdivision and was only 20 years old; and there were not any outstanding liens. I might have gotten lucky - maybe some others can provide feedback on that method....
But if you are buying vacant land or at auction or there are tenants - all those things present specialty issues