The possibility of limiting the memory of nonlinear nonaging viscoelastic materials is discussed. If the deformation histories are bounded, then the memory interval −∞ < τ ≤ t can be reduced to the finite interval t −d ≤ τ, where d ≥ 0 is the duration of memory. It is shown how the duration in relaxation and creep can be obtained for one-dimensional motions. As an application the duration of memory in relaxation and creep of solid polyurethane is computed from available experimental data. It is also shown that when the functionals are evaluated numerically, the use of the duration reduces significantly the computing time. The case of anisotropic material in three-dimensional motions is also discussed.