If I want to connect the output of a logic gate to the input of another logic gate, do I have to use a current limiting resistor? I would like to connect two NANDs (CD4011) in series and then again with the clock of a flip-flop (CD4013.) If the inputs of a CMOS gate has high impedance I suppose it is safe not to use resistors, isn't it?
You could limit the signal rise time by adding a resistor that would effectively form a RC circuit with the input capacitance. But with short distances and only occasional changes in signal it's unlikely you would be experiencing EMC issues and therefore would not need the series resistors. Adding one won't damage the gates, but will slow operations depending on RC time constant.