No, definitely not. It's not at all practical to elect some one as a president for life. Regular elections are much better than this.
Regular elections ensure that the present president remains well in his own power and doesn't misuse his authority.
Also with regular elections many new candidates will also get the chance to get elected as the president.
Besides, elections present a kind of reward and punishment system, this persuades the government and the president to work for the people , willingly or unwillingly.