Aspects of this disclosure relate to catheter assemblies, that include an inner tube component, an outer tube component that fits over the inner tube component, and a disposable layer of film that isolates the otherwise fluid-exposed portions of the catheter from the fluid it drains. This disposable film can be removed at regular intervals and obviates the need for catheter exchanges as the isolating disposable film, rather than the catheter itself, is removed. The principal characteristic of the disposable film is that it is relatively impermeable to fluid, for example, bodily fluids.