Mixing using numbers


I’ve always had a problem mixing music using numbers such as making sure my kick starts at -6dB and everything else follows. And then I recently learned to just have the mix set to a certain level where if you insert a compressor, if it’s reducing the gain a lot to turn it down, and then the mix bus the same thing. Is this the way to go about it? Or do you just go in not worrying and turning levels down when you see levels get too hot.