I dont know how people progress without them,you have to know modes/scales is you want to have a decent jam and come up with new stuff,plus it helps you work out what other people are playing.I have a similar way of writing as Brian Eno where i use oblique strategie cards,i will only try making up basslines using phrigian one week and then say Dorian the next,this way i stay on top of all of them and can pulll them out the bag if i want to show off.