Odds of Hanging On
After your initial training, you'll typically spend six to eight years working in a field office. For your first assignment, you could be sent anywhere in the United States, so you might not want to take out a mortgage just yet.
Once you survive that, you'll jump into a protective assignment for another three to five years. Then you'll go back into the field, in a D.C.-to-field office commuter plan that would put Anthony Bourdain to shame. You might rack up some impressive air mileage.
If you survive all of that to the midpoint of your career, you're probably not going anywhere. However, if the president doesn't survive, it doesn't matter how long you've been working; you're probably not getting called in the next day.