Parts are expensive, and here in Canada repair shops are extremely scarce and very long distances apart. I just discovered that apparently to replace a connecting rod bearing I may have to buy a crankshaft .. $180 new . not a good recommendation. Once you're past the basic maintenance it becomes increasingly difficult to do your own repairs because custom made tools are required, including bearing pullers.
However, Tomos is built very strong, and under normal use should last nearly forever. There may be a problem with the new model, A55 engine's oil pump 'clutch'. It had been reported to wear out at 500 miles, and Tomos is said to be unwilling to create a replacement.
'Powering up' your engine with speed kits is likely to cause more wear and repair.