I am surprised that training aircraft do not have a built in, clear and easy to use stopwatch/clock (ideally with a moveable bug) alongside the other basic flying instruments as standard. Accurate timekeeping was part of my navigation training I seem to remember, which is a rather major part in learning to fly!
But for my PPL, I bought a simple £35 Casio digital watch with stopwatch function, as I found my analogue watch had a cluttered dial and was not easy to read in flight.