Remember in some cities, street names have changed in the last 150 years, houses have been renumbered, interstates have been built, etc. Make certain when using contemporary maps that you know what that 1860 address for your ancestor would be in modern times. Get it converted if you are unable to do it yourself. You may even discover that your ancestor's former residence is now part of an interstate.
Even those with rural ancestors need to remember that county lines, township lines, may change--especially in the early days of settlement.