In order to know what to offer on a property, you must know the condition of the property.  It is not enough to  see a property and say it looks okay.  You must know the underlying conditions of the house.  Can you do this yourself?  In some cases you can.  If you are a very experienced investor, you may know what to look for.   Or, if you are already experienced with construction, or some of the trades, you can probably inspect a home yourself.  But, if you are a beginner, or are not knowledgeable in some areas, you need to hire an inspector, or a building contractor who is knowledgeable in all areas to do the inspection, and give you a report.  You should check with other investors, or realtors to get a good recommendation of a property inspector.  It is also helpful if the inspector understands the business of real estate investing, rather than just retail sale inspecting.

     Many experienced inspectors will do the preliminary inspection themselves, before their offer, but have a professional inspector check the property during the inspection period allowed for in the contract.  There is a very detailed house data form available for printing, or downloading to aid in the inspection of  the property.  Other items, not on this form are checking for termites, mold, radon, or toxic chemicals due to illegal drug labs.  Some of these things will need a separate test, or inspection by someone in that field.

     I would also suggest to make notes, take pictures, and make a notation of the cost to repair, or update, if you know that data.  If you don't know "off the top of your head" this is another area you will have to get data on to complete your due diligence.  The more you know about the property, the better you will be able to determine if the property  will fit your investment needs.