Especially for starters, the work for a saltwater aquarium and freshwater is the same. However, if you put off the work for the saltwater aquarium, the fish will suffer.
So, what work has to be done? You want to make sure you check the filter and change the water. Especially in saltwater tanks, you want to change the water so the pH balance does not drop. If it drops, the fish will not be able to tolerate the change. Although, the water would need to be changed in either tanks. Saltwater tanks do have to be cleaned more frequently due to the plants and bacteria competing.
If maintenance is done regularly, there will be less problems. It is when maintenance is not done that saltwater tanks become more difficult.