Thank you all for your answers.
Badrad, my Dahon is on the second set of cables, second chain, and now is having a second set of brakes installed.
Jur, thanks for the tip with the tape.
Lucille, I like Tikit very much, and as long as the frame doesn't break, I wouldn't mind a little bit of flex. My concern with its 16"-wheels is how well they handle going over cracks, potholes, bumps, and curbs that are not slanted properly. With my 20" Dahon I had a close call when the front wheel wouldn't roll over a diagonal ridge in the pavement properly and instead decided to follow the ridge. My big (second) bike doesn't have this issue. With wheels 4" smaller this could be even worse; poor-quality pavement, such as on Queens Quay in Toronto, could present a big challenge to Tikit.
I bought the Dahon at Urbane Cyclist. It seems like a nice bike shop, though it's true the saleperson didn't give me much info about the advantages/disadvantages of the folding bike models they had.