Changing Vaccum lines and hoses

Have any one had any problems with your car from changing out the old factory vaccum line and hoese? I notice like the fan will come on sooner when it is still cold. Why change lines and hoeses because they have never been changed sense I had the car and my oil cooler line brust and I replace the whole thing. Cooler and all.

3sx has a silicon vacuum hose kit that work very well but it will take two (2) kits to do most of the vacuum lines on a VR4. Have fun!