Dishwasher not cleaning dishes well all of a sudden

Dishwasher Repair
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1

I have a GE dishwasher, Model GSD640G-01. It was in my apartment when I bought it and I’ve been here 9 yrs. I alwyas had to rinse the dishes before putting them in, as food particles would end up on the dishes if I didn’t. Now, even with rinsing them, the dishes are not coming out too clean. Unsure if it’s worth trying to fix or just buy a new one?? Just realized I recently had to replace my sink pipe, which may have been when this problem recently started. I will tighten the hose, but unsure what else I should do? Please help!