Kenmore dishwasher Model series 16785

I'm not sure which in this model series we have. I'm not even sure exactly when we got it. It is between 15 and 20 years old. It has been good. I see that it was repaired in 2012, but only one time, until now. The door springs have been replaced, by us, several times. We have to clean the dishes well before putting them in the dishwasher. It has always been that way. That was nothing different than we expected, though. It seems to me that the cleaning has gotten worse over time, so we've had to be more thorough with pre-cleaning. It's certainly louder that dishwashers now a days, but it was good in it's time. We are replacing it now because the gasket has gone bad and it is leaking. We had a repairman out, not Kenmore specific, and he had never worked on one this old, even though he has 14 yrs owned his business. The gasket had totally disintegrated into many pieces when he found it. We had ordered in a new Kenmore gasket part, my husband thought that was the problem based on the parts booklet, but it was hard to replace for our serviceman. Now the dishwasher leaks even more, so we decided to replace it knowing the new ones are quieter, clean better and save more water.