The most important thing you can do in terms of reliability and longevity with your vehicle is servicing and maintenance. Regular servicing, ideally more frequently than the recommended intervals, using manufacturer-specification products, gives your vehicle the best chance of remaining trouble-free. Premium quality parts may help to a small degree, but not skimping on the quality of components is more beneficial than spending more on parts that are higher specification than the original items. If possible, storing your car in a garage would also contribute to reliability - keeping your car in a more controlled environment helps to protect the bodywork and avoiding extremes of temperature and weather means perishable components such as seals and bushes will experience less degradation over time.