If your boxer's battery and electricals are healthy, it should start within a crank or two. Your current battery may have a date stamp on it, as to when it was installed, and if it is fewer than 5 years old, it may still be OK. I would have an electrical expert test it, to be sure, before spending money on a new one.
I just bought a used R1200ST, with no service history, and I had to take the battery right out to find a tiny little date stamp on the bottom. It was only 2 years old.