Similar here... I had one large (master) TODO file and one large IDEAS file and I would move tasks from TODO file on my daily TODO list. The IDEAS file grown to more then 50 pages and I rarely read it... :-)
Nowdays I moved to paper so NSA can not read my ideas and tasks anymore. For TODOs I use one paper sheet per project/subject and carry all these 10-12 sheets in a folder. Then I move the tasks on my daily TODO list in Moleskine... For IDEAS: I draw/sketch/write them on paper and store them in archive folder (just in case I need it)... :-)