After having briefly surveyed the different techniques the most commonly used in deep inelastic studies the problem of the body number in the exit channel is discussed. There are now strong experimental evidences that only two major nuclear pieces are left at the scission stage whatever is the size of the nucleides in the entrance channel. Then, among the most three relevant collective degrees of freedom involved in deep inelastic collisions (mass asymmetry, relative motion, neutron to proton ratio) the last two ones which appear to be rather rapidly relaxed are considered. The time evolution is looked at by surveying the individual nucleus yield distributions as a function of their kinetic energy and angular distribution. A tentative classification of the interacting systems based on the angular distribution pattern of the products is given as a function of a Sommerfeld-like parameter. The action of the viscous forces which are responsible of the kinetic energy damping is investigated through the analysis of the internal degrees of freedom of the reaction products (excitation energy, deformation energy and spin). Finally the relaxation of the neutron excess degree of freedom is shown to be very rapidly achieved (even more rapidly than is the relaxation of the degree of freedom associated to the relative motion)