Lifetime of various dust sizes, from different starting positions in a Weidenschilling (1977) style disc. Here, the lifetime is calculated as the reciprocal of the terminal radial velocity of the dust: |$\tau = \left(\frac{dR}{dt}\right)^{-1}$|⁠. On average, our numerical models agree with those in Weidenschilling (1977) to within 3 per cent. The following parameters were used to reproduce the plot: |$M_*=1M_\odot$|⁠, |$\rho = 10^{-9}$| g cm|$^{-3}$|⁠, density power law |$a=2$|⁠, |$T_0=600$| K, temperature power law |$m=1$|⁠, |$\mu =2.25$|⁠, |$\rho _s = 3$| g cm|$^{-3}$| and |$\sigma =3.85 \cdot 10^{-15}$| cm|$^2$|⁠.