Fractional precision of a distance measurement for weekly observations with TOA errors of 10 ns up to a distance of 3 kpc. Beyond 3 kpc, we assume the timing precision to become worse by a factor scaling with the square of the distance. Colours indicate the length of the observing span: 5 yr (blue), 10 yr (red), and 15 yr (green), respectively. The thick lines indicate the kinematic distance measurement for a pulsar in a 1 day orbit with an 0.3 solar mass companion. The thin lines indicate the timing parallax for the same pulsar. Note that the 10-yr lines (red) overlap.