I've heard people say you don't need to rinse, but from experience this just doesn't seem to be true, or at least it's based on the dishwasher you have. I had a dishwasher 15 years ago where I tested the idea of not rinsing vs rising, and if I didn't rinse, I would sometimes have dishes that weren't completely clean (ie, hot chocolate residue in a mug, cheese from mac n cheese on silverware, etc).
I find small food particles left on the top rack if I don't rinse. These are easy to remove (not baked on), but are super annoying and I can't understand why except that when rinsing it's reusing dirty water and not finishing with a clean rinse.
My dishwasher sends the water into the waste disposal built into the sink. If the waste disposal has a lot of food that hasn't been grinded it up, it seems to slow the draining of the dishwasher so not all the food gets drained before the rinse cycle. So I learned to run the waste disposal for a couple seconds before starting a dishwashing load.
