While both characters lead double lives the way they go about creating their facades are entirely different. Jack lives a very respectful life in the country and is the guardian and mentor for his niece Cecily whom he cares very much for. He is seen as very mature and is sometimes quite bored with this lifestyle. In order to escape this, Jack creates his younger brother Earnest who lives and London and lives a very reckless and exciting life. Jack says that when he goes to London it's for him to look over his brother, but instead it's for him to go and meet the women who he loves named Gwendolen Fairfax. Gwendoen is in love with the name Ernest so he instead says his name is that, adding onto the list of things that aren't true. Jack lies to both his love and his niece in order to keep his double life alive, causing him to contradict himself in many situations, as his lies finally catch up to him as Gwendolen and Cecily confront each other, leading to the fall of his double life. Jack's attitude represents the Victorian period, as his double life from the country to the city shows the facade of respectability people felt they had at the time.
Algernon's motives for his double life are to escape his social obligations in the city and relax in the country. Instead of a brother like Jack, Algernon creates a friend named Bunbury who he frequently went to visit so he wouldn't have to attend dinner with his aunt, Lady Bracknell. Bunbury is always on the verge of death in order for him to miss any social event he doesn't wish to attend. Wilde shows the clear disdain for respect in the Victorian period through Algernon, who carries his life in such a carefree manner, leading him to live a double life.
As it can easily be seen, Oscar Wilde clearly had a purpose behind the plot of The Importance of Being Earnest as it was to satirize the Victorian society's hypocritical and superficial aspect through the two bachelor's double lives. The physical journey from the countryside to the city allowed to this to be shown, as Jack still wanted to be respected even when living the double life. They both created fictional characters in order to show this as well. All these aspects implemented together helped show Wilde's criticism on the hypocritical nature of the Victorian society.
