If you can strike up a good relationship with a good repair technician, show that you have an obvious interest in how the repairs are done and how the machines are put together, and show that you genuinely appreciate the skill it takes to repair the machines, you can get valuable lessons in how to troubleshoot and repair the machine for yourself the next time around.
Also, most machines are designed to be easily built, not to be easily maintained. This is part of a design and product life-cycle philosophy that ties in to product pricing, market segmentation, regulatory requirements, etc. I recently tried fixing a tumble dryer for my father-in-law... A horrible design, with a condenser at the bottom with a first reservoir and a pump to send the water up to a second reservoir at the top that is removable for emptying. Why not have the water go straight to the removable reservoir at the bottom? And the pump that had failed is inside a housing that I could only have got to by removing the motor and the drum... I'm sure that the pump fails more frequently than the motor or drum.
I've worked on the maintenance manuals for medical laboratory machines; working from the drawings that were supposed to be the "final" versions, and comparing to the machines that had just been manufactured, I found a number of deviations that had been approved in order to make manufacturing easier, and others that had been introduced to make servicing easier.
There's a big difference, between the lab machine and dishwasher in the design philosophy, a fair difference in the precision of dosing the detergent, controlling the temperature, and squirting the water around, very little difference in the panelling and the buttons that the operator has to push.