I don't think you need to record your solves as long as you have some way of recording your times, be it watch, stopwatch, timer, csTimer, qqTimer, phone stopwatch, smart cube (which, as I will warn you, is technically against WCA regulations), oven timer, microwave timer, doing trigonometry using the angles of the Sun before and after your solve, alarm clock, calendar, Spotify playlist, egg timer, toaster oven, hourglass, a known file download time, A Series Of Unfortunate Events episode, friend, Stackmat timer, or other.
(Less than half of those would actually be viable, so don't use those unless you absolutely have to.)