Bearhunter's post is excellent.
While I have owned a number of magnums over the years, I own and have shot more game with non-magnum cartridges, and am down to just a few today...too much experience and sentiment in them to let them go. And a review of all my big game harvests over the years (38), ranging from 5 to 475 yards (underestimated the range on that one), my average shot distance is just 137 yards.
But wanting a magnum is not a bad thing, and for elk, brings a safety margin in increased retained energy with a heavier bullet that will provide better penetration if the shot encounters bone, or at longer distances...not to mention buying another rifle is always an exciting prospect!
And until you experience owning, loading, shooting, and hunting with one, yuu will not be able to determine if it is truly for you, or not.
When it comes to long range hunting, I have my own limits (ethical and physical), and I prefer to not shoot beyond 400 yards at unwounded game. If the animal is further out, I try to get closer, or not take the shot. But this is my personal limitation that I place on myself. I can, and do, practice out to 500 yards, but mostly to build skill and confidence that pays dividends for shorter distance shots.
Best of luck in your quest!