Is there a limit to the quantity of text one can write in Stickies? I've gotten into the (bad) habit of writing for hours within Stickies. It's fast to start up, uses very little RAM, doesn't distract me with bells and whistles or obtrusive GUI, it auto-saves, and the windows can be usually very small, which I like.

Some of my notes are becoming rather large, however, and I am wondering if there's a limit to the quantity of text one can write in Stickies (with the default font and font size). Or if the limit may be assigned to the overall quantity of text within all Stickies notes combined.
There shouldn't be. The only issue you may incur is writing too much for your RAM to handle, but that's into if you write gigabytes unto gigibytes of raw text. 
The average user shouldn't.