Several J-estimation procedures for use in the presence of stable crack growth are reviewed to show the distinction between those based on internal energy or on work done and on the choice of “incremental” or “sequential” analysis. These are then related and compared theoretically and experimentally to show very little differences between them for the J-controlled regime with small amounts of growth. For large amounts of growth, rising and drooping R-curves are discussed using data from open literature. A deformation theory J is shown to give a drooping R-curve shortly after ω < f(η). Two recent expressions for J, J_m, and J_a, formulated to satisfy the Rice, Drugan, and Sham criterion of ˙J_pl ≠ f(˙a), are discussed in light of these arguments. Finally, a reinterpretation of R-curves is discussed for large amounts of growth suggesting Δa/c for the R-curve abscissa instead of Δa with the view to obtaining a geometry-independent R-curve.