You may not have ever realized this--I didnt until we had been in our house almost 2 years--but even your dishwasher needs regular maintenance and cleaning to keep it at its best.
I clean out our dishwasher every few months to avoid calcium and lime build up, using the Works, which I get from the dollar store for--that's right--a dollar. I Turn the Dishwasher on, let it run to the Wash Cycle; then put in 8 oz of cleaner--I use the whole bottle of the Works, since it is only a dollar--and allow the wash cycle to finish. Using a very hard bristled brush--small screwdriver if needed--scrub the holes, removing any leftover calcium build up. I also clean out any debris from the bottom and wipe down the sides and door. Finally, I run a "quick" cycle to finish the job.