This decision belongs to your surgeon, twice over, and the wording is worth reading exactly.
On the first dressing: you can leave your original dressing in place for as long as your surgeon says.
On stopping altogether: at some point during the healing process, you will not need a dressing anymore, and your surgeon will tell you when you can leave your wound uncovered.
Between those two points, your surgeon will tell you how often to change it. So there are three separate decisions: when the first dressing comes off, how often it is replaced, and when it stops being replaced. All three belong to the same person.
There is one circumstance in which you should act without waiting: you will want to change the dressing sooner if it becomes wet or soaked with blood or other fluids.
And one for washing: remove the dressing before bathing unless told otherwise. Some dressings are waterproof, and your surgeon may suggest covering the wound with a plastic bag to keep it dry instead.
The reason this is not left to judgment is in what a dressing is doing. Dressings protect the wound from germs, reduce the risk of infection, cover the wound so that stitches or staples do not catch on clothing, protect the area as it heals, and soak up fluids that leak from the wound. Whether those jobs are still needed is a question about the wound, not about how it looks from outside.