Like can they plan vacations. When does work start and end. Are they always on-call?
Can they call in sick for the whole day?
I can't tell if you are talking about residents or attendings. The answer is very different depending on that.
Residents are required to have vacation time every year. Attendings are not.
As a resident, your chiefs will schedule your vacation time according to the master schedule, usually in 1 week blocks. Note that a "week" does not necessarily have to include weekends around it. But at least this allows you to plan a trip, assuming you have the money to do so.
As an attending, well, there are no rules. Those who work more and harder make more money (all else being equal), particularly early in your career. So many attendings don't get much (if any) vacation time, unless they work for a very large practice or an academic setting. Even then though, someone has to cover for you, and let me tell you that coverage is not fun. Sometimes the hassle of organizing coverage and extricating yourself from the practice for a few days isn't worth the potential gain of a vacation.
Regarding sick days in residency, it's not like you get X number of sick days in residency, as you would a normal job. Some programs do have allowances for "personal days" but this is not the norm. Remember that residents are usually stretched pretty thin to cover the hospital and clinics, and so the unexpected removal of one resident from the pool, even for one day, can cause a huge increase in the work of the remaining residents. As a result (and I'm not necessarily advocating this) many residents work sick to avoid dumping on their classmates. This is why you see residents on rounds with IVs, taking quick breaks to go vomit. This is also why whole residency classes come down with the flu at the same time. However, from the other side of it, when you're already stressed to near the breaking point, having someone call in sick for less than a missing limb and dump a busy service on your lap can result in significant resentment and occasionally blind rage. It is difficult to find a good balance between taking time off when you need it, and trying to tough it out.