How about for the believer? Of course you don't have too worry about making the decision to follow Jesus before He returns, because you've already made the choice. But how are you living your decision out? We should, in my opinion, be living out each day as if it's our last: loving people to the best of our ability, taking every opportunity to share the gospel, and also being Jesus' hands and feet in every way we can. The opportunities for us to obey and serve isn't to secure our salvation, as we know that it is not by our works that we are saved, but by the grace of God. However, if we don't take the opportunity to reflect Jesus, then who might miss out on hearing or seeing the gospel lived out if we choose to overlook an opportunity or choose to walk away from a situation in which we can serve, love and share the gospel? Of course God doesn't need us to bring someone to Himself, but He does use us so that we can share in what He is doing, and be blessed also. Jesus might return in the next hour, and by not taking opportunity placed in our path, we would miss His calling to share the Good News.
Since we don't know the day or hour, and unbelievers still exist, we need to act as if we know Jesus is coming soon, to get our hearts in expectation, preparation and obedience to share with the unbelieving in this world before that hour does come and they are without hope.