COMMUTER ACFT EXCEEDS ASSIGNED ALT.

Narrative

ALTHOUGH 10000 FT MSL IS CONSIDERED TO BE BOUNDARY FOR CRITICAL PHASE OF FLT; MANY ARPT'S HAVE HIGH WORKLOAD UP THROUGH MAYBE FL200; DENVER IS NO EXCEPTION. I'M CONSTANTLY TELLING COPLTS I FLY WITH TO NOT PERFORM DISTRACTING DUTY'S THAT ARE NOT NECESSARY UNTIL WE LEAVE THE BUSY AREA OF DEP CTL AND LEVEL AT CRUISE WITH CTR. SINCE COMPANY ALLOWS CREWS TO DO THEIR OWN THING; COPLTS WILL FLY WITH ONE CAPT WHO LIKES MUSIC FROM GATE TO GATE; TO CAPT'S AFTER TKOF CLOSING DOORS AND PULLING MAGAZINE OR NEWSPAPERS. SO SINCE COPLTS GENERALLY PICK HABITS OF THE PEOPLE THEY FLY WITH; A POOR HABIT PATTERN IS DEVELOPED FOR SAFE; VIOLATION FREE FLT; AS MY COPLT LEAVING 10000 FT CALLED COMPANY WITH DEP TIMES AND GRABBING TRIP LOG BEFORE I KNEW IT ASKING ME NUMBER OF PEOPLE ETC. (THE STAGE WAS SET). AT THAT INSTANT CLBING OUT OF 12200 (ASSIGNED FL120) I SAID HOLY XXX. STARTED CORRECTING (12300 PLUS) APCH CALLED AND AMENDED OUR ALT TO FL130. NO CONFLICT WAS EVIDENT WITH ANY OTHER ACFT. I'VE DECIDED FOR NOW I'M HIDING TRIP LOG UNDER MY SEAT; OUT OF REACH! AS A SIDE NOTE THE ALT ALERT GIVES A TONE AND LIGHT AT 1000 FT TO GO AND LIGHT ONLY FOR ASSIGNED ALT. WE HAVE FLT DIRECTORS; BUT NO ALT CAPTURE CAPABILITY.