The paper on crustal recycling by DePaolo (``The mean life of continents...'' Geophys. Res. Lett. 10, 705-708, 1983) contains errors in the listing and plotting of published Hf isotopic data which materially affect the inferred pattern of mantle Hf isotopic evolution. More generally, the impression given in the paper that it is now possible to use Nd and Hf isotopic data to constrain the degree of crust-to-mantle recycling is misleading because exactly the same observed effects would be produced by mixing within the mantle itself. Existing Nd and Hf isotopic data alow either crustal growth with no recycling of crust to mantle, or a model of constant-mass continental crust with extensive recycling. This implies that all intermediate growth plus recycling combinations are also permitted.