I'm the dishwasher in my house, I don't want to be replaced!

On a serious note, if you can do a bit of research on your current model, you might be able to calculate with some certainty how much energy and water you might save with a newer one. Also, some utility companies offer incentives to replace old appliances with new EnergyStar models.

It might make sense, especially if you use it a lot, to replace it, but sustainability and economic arguments can also be made in favor of sticking with your current unit.

one way to get a lot of the gunk out of a dishwasher is to fill it, then suck the water out of the sump with a shopvac. also make sure all the holes in the spray arms are clear.
you can run it empty with white vinegar, or the big guns, some clr.

to keep up with all the latest fads.

If you have enough money, when you get sick of the noise, it leaks, or a cleaning won't fix its defective action.

If you have no money, when the duct tape don't hold.

maybe something needs cleaning inside. Or, maybe it's just worn out and a new one is in order. The newer ones are more energy-efficient and have more options for using less water. I recently remodeled my kitchen and wanted to save a little money by keeping my old dishwasher, but we discovered it was so old that the parts needed to install it were no longer available. So I broke down and bought a new one - and it cleans way better than the old one did. I guess I'd become so used to dishes that didn't always get clean the first time and having to run them through again that I thought it was normal. But my new one cleans so much better, and it's also much quieter. So if you can afford it you might just want to get rid of the old one.

It all depends on the how many years it has been used, so can you please tell when did you buy it, as it will tell when to change the dishwasher.

Hi, if your dishwasher doesn't clean well the culprit may very well be your detergent. Also if you're in an area where there's a lot of hard water this might be your problem. If there is anything clogged inside you might as well call someone to fix the clog. Here is some more info on the subject.
http://www.familyhandyman.com/appliance-repair/dishwasher-repair/dishwasher-repair-tips-dishwasher-not-cleaning-dishes/view-all