Should you do your own pre-purchase inspection? Yes and no. Yes, you should inspect a house before you write an offer on it. Then you should put an inspection contingency clause in the offer, and hire a professional inspector. Why do both?
Doing your own inspection can help you get a better deal. Each cracked window or leaky toilet you can find is a negotiating point. You see, you could just make a low offer, but a seller is more likely to accept your offer if you have reasons for it being lower. In fact, you should attach a list of your concerns to the offer, as an explanation and justification for your price.
Use a list as you walk through the house. Using a home inspection checklist keeps you from forgetting things. You don’t have to know the difference between 12-gauge and 14-gauge wiring, or become an expert on all the building trades, as useful as this would be. Just use what you do know, and make a note if something looks “odd” or “smells funny.” Afterwards, you can have a professional inspector take a closer look.
Pay for a professional pre-purchase inspection. Unless you really know a lot, it can save your neck...