For me, anything recent or modern is not an option. My criteria for motorcycles is kick start and air cooled. I like simple, reliable vehicles that are easy to maintain. I value function, as well as the beauty that 70s or older bikes have. A modern 600 sport bike will not fit the bill, even into the 80s many motorcycles became more difficult to service and less reliable particularly as kick starts disappeared. Dirt bikes are an exception, I have a couple 80s dual sports that are comparable to 70s street bikes and strike me as the best era for maximum HP at the lowest weight with modern suspension that is easily upgraded.
My sentiment for what qualifies a four wheeled vehicle as serviceable is similar: Vent windows, floor vents, manual windows, carburetor or mechanical fuel injection. This limits options to 60s and 70s, or into the 80s for trucks (similar to dirt bikes, trucks took another decade to get the ugly and difficult to service treatment that dirt bikes got).
Different strokes for different folks and all, but that being said I stick to vehicles that I believe I'd be happy to use for the rest of my life. A modern 600 sport bike would surely be fun to ride now and again but I'd want to be rid of it before it needed any major servicing (that would be considered minor servicing on an older model). I suppose a new disposable bike could be useful for winters when there is often salt on the roads, but it's more cost effective to just maintain what you've got than replace new expensive stuff frequently.
