The truth is most engine oil that you find in the market will already have the basic additives in it. So, if all you want is to make your car run and if you do change the oil on time, you need not spend the extra money on oil additives. But additives can give a significant boost to your car’s performance and will also improve the longevity of the engine. If high performance and longer intervals between the services is important for you, then the money you spend on additives is worth every penny. Another area where additives shine is in fixing the old and clogged up engines.