Time for new wheels and tires

I have heard and read about mixing radials and bias ply tires all my life , and know the tire manufacturers don't recommend it . I have mixed them over the yrs. on 2 hemi cars, hot sbc`s , a 440 coronet , vega , pickups , and now my barracuda , switched back and forth and cant tell any diff .
Maybe if I drove like a teenager , did the road race thing when I was young, don't do it now , mostly hi way and straight line speed . ??????
is wonder if the difference would be if you had say 1 bias and 1 radial up front, vs having different types front vs rear