I know I don’t sketch everyday and I blame it on the lack of time. Solution: very fast sketching 
I found good advice in David Rankins book Fast sketching Techniques. And the book I came across at http://www.stutler.cc/ site. He has a wealth of information on sketching and there is an obvious risk of losing all the time there that you were supposed to gain by sketching fast
EggMachine
ChickenMakingMachine
Happy sketching if you ever leave Russ’s site