Several of the guys that I started out with went on to the USSS. I've also worked along with the USSS on a few former-POTUS visits and for the G8 Summit.
POTUS election years can be brutal. At the time I had contact, they worked a 28 straight day schedule.
One night, one of the guys from the old days was bored and called the squad room. He was on midnight shift standing outside of a bathroom window of a house because the POTUS was staying there for the night.
While not every agent works protective details as their normal assignment, if POTUS, V-POTUS or a former POTUS comes to town, they get pulled for the detail.
I was standing guard over the arrival area for a former POTUS visit along with several agents and got to chat with them a good bit. A former V-POTUS who less than a mile away at a different event. They told me that with a few exceptions, the actual elected official were typically easy going but that the junior staffers could be a real pain and would try to treat them as armed porters. If it got too bad, they'd a senior guy to reign in the youngster.
One of the guys I had been a rookie with was on the above mentioned detail. He was sitting in a room making sure that the cell phone jammer worked. He later wound up on Obama's detail just as he was leaving the White House; so, my buddy spent a lot of time in Hawaii over the next few years. I'm not sure of his current assignment or if he got to have any fun on the islands.